GNU Free Documentation License

                  Version 1.3, 3 November 2008

  Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.

      <http://fsf.org/>

  Everyone is permitted to copy and distribute verbatim copies

  of this license document, but changing it is not allowed.

 0. PREAMBLE

 The purpose of this License is to make a manual, textbook, or other

 functional and useful document "free" in the sense of freedom: to

 assure everyone the effective freedom to copy and redistribute it,

 with or without modifying it, either commercially or noncommercially.

 Secondarily, this License preserves for the author and publisher a way

 to get credit for their work, while not being considered responsible

 for modifications made by others.

 This License is a kind of "copyleft", which means that derivative

 works of the document must themselves be free in the same sense.  It

 complements the GNU General Public License, which is a copyleft

 license designed for free software.

 We have designed this License in order to use it for manuals for free

 software, because free software needs free documentation: a free

 program should come with manuals providing the same freedoms that the

 software does.  But this License is not limited to software manuals;

 it can be used for any textual work, regardless of subject matter or

 whether it is published as a printed book.  We recommend this License

 principally for works whose purpose is instruction or reference.

 1. APPLICABILITY AND DEFINITIONS

 This License applies to any manual or other work, in any medium, that

 contains a notice placed by the copyright holder saying it can be

 distributed under the terms of this License.  Such a notice grants a

 world-wide, royalty-free license, unlimited in duration, to use that

 work under the conditions stated herein.  The "Document", below,

 refers to any such manual or work.  Any member of the public is a

 licensee, and is addressed as "you".  You accept the license if you

 copy, modify or distribute the work in a way requiring permission

 under copyright law.

 A "Modified Version" of the Document means any work containing the

 Document or a portion of it, either copied verbatim, or with

 modifications and/or translated into another language.

 A "Secondary Section" is a named appendix or a front-matter section of

 the Document that deals exclusively with the relationship of the

 publishers or authors of the Document to the Document's overall

 subject (or to related matters) and contains nothing that could fall

 directly within that overall subject.  (Thus, if the Document is in

 part a textbook of mathematics, a Secondary Section may not explain

 any mathematics.)  The relationship could be a matter of historical

 connection with the subject or with related matters, or of legal,

 commercial, philosophical, ethical or political position regarding

 them.

 The "Invariant Sections" are certain Secondary Sections whose titles

 are designated, as being those of Invariant Sections, in the notice

 that says that the Document is released under this License.  If a

 section does not fit the above definition of Secondary then it is not

 allowed to be designated as Invariant.  The Document may contain zero

 Invariant Sections.  If the Document does not identify any Invariant

 Sections then there are none.

 The "Cover Texts" are certain short passages of text that are listed,

 as Front-Cover Texts or Back-Cover Texts, in the notice that says that

 the Document is released under this License.  A Front-Cover Text may

 be at most 5 words, and a Back-Cover Text may be at most 25 words.

 A "Transparent" copy of the Document means a machine-readable copy,

 represented in a format whose specification is available to the

 general public, that is suitable for revising the document

 straightforwardly with generic text editors or (for images composed of

 pixels) generic paint programs or (for drawings) some widely available

 drawing editor, and that is suitable for input to text formatters or

 for automatic translation to a variety of formats suitable for input

 to text formatters.  A copy made in an otherwise Transparent file

 format whose markup, or absence of markup, has been arranged to thwart

 or discourage subsequent modification by readers is not Transparent.

 An image format is not Transparent if used for any substantial amount

 of text.  A copy that is not "Transparent" is called "Opaque".

 Examples of suitable formats for Transparent copies include plain

 ASCII without markup, Texinfo input format, LaTeX input format, SGML

 or XML using a publicly available DTD, and standard-conforming simple

 HTML, PostScript or PDF designed for human modification.  Examples of

 transparent image formats include PNG, XCF and JPG.  Opaque formats

 include proprietary formats that can be read and edited only by

 proprietary word processors, SGML or XML for which the DTD and/or

 processing tools are not generally available, and the

 machine-generated HTML, PostScript or PDF produced by some word

 processors for output purposes only.

 The "Title Page" means, for a printed book, the title page itself,

 plus such following pages as are needed to hold, legibly, the material

 this License requires to appear in the title page.  For works in

 formats which do not have any title page as such, "Title Page" means

 the text near the most prominent appearance of the work's title,

 preceding the beginning of the body of the text.

 The "publisher" means any person or entity that distributes copies of

 the Document to the public.

 A section "Entitled XYZ" means a named subunit of the Document whose

 title either is precisely XYZ or contains XYZ in parentheses following

 text that translates XYZ in another language.  (Here XYZ stands for a

 specific section name mentioned below, such as "Acknowledgements",

 "Dedications", "Endorsements", or "History".)  To "Preserve the Title"

 of such a section when you modify the Document means that it remains a

 section "Entitled XYZ" according to this definition.

 The Document may include Warranty Disclaimers next to the notice which

 states that this License applies to the Document.  These Warranty

 Disclaimers are considered to be included by reference in this

 License, but only as regards disclaiming warranties: any other

 implication that these Warranty Disclaimers may have is void and has

 no effect on the meaning of this License.

 2. VERBATIM COPYING

 You may copy and distribute the Document in any medium, either

 commercially or noncommercially, provided that this License, the

 copyright notices, and the license notice saying this License applies

 to the Document are reproduced in all copies, and that you add no

 other conditions whatsoever to those of this License.  You may not use

 technical measures to obstruct or control the reading or further

 copying of the copies you make or distribute.  However, you may accept

 compensation in exchange for copies.  If you distribute a large enough

 number of copies you must also follow the conditions in section 3.

 You may also lend copies, under the same conditions stated above, and

 you may publicly display copies.

 3. COPYING IN QUANTITY

 If you publish printed copies (or copies in media that commonly have

 printed covers) of the Document, numbering more than 100, and the

 Document's license notice requires Cover Texts, you must enclose the

 copies in covers that carry, clearly and legibly, all these Cover

 Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on

 the back cover.  Both covers must also clearly and legibly identify

 you as the publisher of these copies.  The front cover must present

 the full title with all words of the title equally prominent and

 visible.  You may add other material on the covers in addition.

 Copying with changes limited to the covers, as long as they preserve

 the title of the Document and satisfy these conditions, can be treated

 as verbatim copying in other respects.

 If the required texts for either cover are too voluminous to fit

 legibly, you should put the first ones listed (as many as fit

 reasonably) on the actual cover, and continue the rest onto adjacent

 pages.

 If you publish or distribute Opaque copies of the Document numbering

 more than 100, you must either include a machine-readable Transparent

 copy along with each Opaque copy, or state in or with each Opaque copy

 a computer-network location from which the general network-using

 public has access to download using public-standard network protocols

 a complete Transparent copy of the Document, free of added material.

 If you use the latter option, you must take reasonably prudent steps,

 when you begin distribution of Opaque copies in quantity, to ensure

 that this Transparent copy will remain thus accessible at the stated

 location until at least one year after the last time you distribute an

 Opaque copy (directly or through your agents or retailers) of that

 edition to the public.

 It is requested, but not required, that you contact the authors of the

 Document well before redistributing any large number of copies, to

 give them a chance to provide you with an updated version of the

 Document.

 4. MODIFICATIONS

 You may copy and distribute a Modified Version of the Document under

 the conditions of sections 2 and 3 above, provided that you release

 the Modified Version under precisely this License, with the Modified

 Version filling the role of the Document, thus licensing distribution

 and modification of the Modified Version to whoever possesses a copy

 of it.  In addition, you must do these things in the Modified Version:

 A. Use in the Title Page (and on the covers, if any) a title distinct

    from that of the Document, and from those of previous versions

    (which should, if there were any, be listed in the History section

    of the Document).  You may use the same title as a previous version

    if the original publisher of that version gives permission.

 B. List on the Title Page, as authors, one or more persons or entities

    responsible for authorship of the modifications in the Modified

    Version, together with at least five of the principal authors of the

    Document (all of its principal authors, if it has fewer than five),

    unless they release you from this requirement.

 C. State on the Title page the name of the publisher of the

    Modified Version, as the publisher.

 D. Preserve all the copyright notices of the Document.

 E. Add an appropriate copyright notice for your modifications

    adjacent to the other copyright notices.

 F. Include, immediately after the copyright notices, a license notice

    giving the public permission to use the Modified Version under the

    terms of this License, in the form shown in the Addendum below.

 G. Preserve in that license notice the full lists of Invariant Sections

    and required Cover Texts given in the Document's license notice.

 H. Include an unaltered copy of this License.

 I. Preserve the section Entitled "History", Preserve its Title, and add

    to it an item stating at least the title, year, new authors, and

    publisher of the Modified Version as given on the Title Page.  If

    there is no section Entitled "History" in the Document, create one

    stating the title, year, authors, and publisher of the Document as

    given on its Title Page, then add an item describing the Modified

    Version as stated in the previous sentence.

 J. Preserve the network location, if any, given in the Document for

    public access to a Transparent copy of the Document, and likewise

    the network locations given in the Document for previous versions

    it was based on.  These may be placed in the "History" section.

    You may omit a network location for a work that was published at

    least four years before the Document itself, or if the original

    publisher of the version it refers to gives permission.

 K. For any section Entitled "Acknowledgements" or "Dedications",

    Preserve the Title of the section, and preserve in the section all

    the substance and tone of each of the contributor acknowledgements

    and/or dedications given therein.

 L. Preserve all the Invariant Sections of the Document,

    unaltered in their text and in their titles.  Section numbers

    or the equivalent are not considered part of the section titles.

 M. Delete any section Entitled "Endorsements".  Such a section

    may not be included in the Modified Version.

 N. Do not retitle any existing section to be Entitled "Endorsements"

    or to conflict in title with any Invariant Section.

 O. Preserve any Warranty Disclaimers.

 If the Modified Version includes new front-matter sections or

 appendices that qualify as Secondary Sections and contain no material

 copied from the Document, you may at your option designate some or all

 of these sections as invariant.  To do this, add their titles to the

 list of Invariant Sections in the Modified Version's license notice.

 These titles must be distinct from any other section titles.

 You may add a section Entitled "Endorsements", provided it contains

 nothing but endorsements of your Modified Version by various

 parties--for example, statements of peer review or that the text has

 been approved by an organization as the authoritative definition of a

 standard.

 You may add a passage of up to five words as a Front-Cover Text, and a

 passage of up to 25 words as a Back-Cover Text, to the end of the list

 of Cover Texts in the Modified Version.  Only one passage of

 Front-Cover Text and one of Back-Cover Text may be added by (or

 through arrangements made by) any one entity.  If the Document already

 includes a cover text for the same cover, previously added by you or

 by arrangement made by the same entity you are acting on behalf of,

 you may not add another; but you may replace the old one, on explicit

 permission from the previous publisher that added the old one.

 The author(s) and publisher(s) of the Document do not by this License

 give permission to use their names for publicity for or to assert or

 imply endorsement of any Modified Version.

 5. COMBINING DOCUMENTS

 You may combine the Document with other documents released under this

 License, under the terms defined in section 4 above for modified

 versions, provided that you include in the combination all of the

 Invariant Sections of all of the original documents, unmodified, and

 list them all as Invariant Sections of your combined work in its

 license notice, and that you preserve all their Warranty Disclaimers.

 The combined work need only contain one copy of this License, and

 multiple identical Invariant Sections may be replaced with a single

 copy.  If there are multiple Invariant Sections with the same name but

 different contents, make the title of each such section unique by

 adding at the end of it, in parentheses, the name of the original

 author or publisher of that section if known, or else a unique number.

 Make the same adjustment to the section titles in the list of

 Invariant Sections in the license notice of the combined work.

 In the combination, you must combine any sections Entitled "History"

 in the various original documents, forming one section Entitled

 "History"; likewise combine any sections Entitled "Acknowledgements",

 and any sections Entitled "Dedications".  You must delete all sections

 Entitled "Endorsements".

 6. COLLECTIONS OF DOCUMENTS

 You may make a collection consisting of the Document and other

 documents released under this License, and replace the individual

 copies of this License in the various documents with a single copy

 that is included in the collection, provided that you follow the rules

 of this License for verbatim copying of each of the documents in all

 other respects.

 You may extract a single document from such a collection, and

 distribute it individually under this License, provided you insert a

 copy of this License into the extracted document, and follow this

 License in all other respects regarding verbatim copying of that

 document.

 7. AGGREGATION WITH INDEPENDENT WORKS

 A compilation of the Document or its derivatives with other separate

 and independent documents or works, in or on a volume of a storage or

 distribution medium, is called an "aggregate" if the copyright

 resulting from the compilation is not used to limit the legal rights

 of the compilation's users beyond what the individual works permit.

 When the Document is included in an aggregate, this License does not

 apply to the other works in the aggregate which are not themselves

 derivative works of the Document.

 If the Cover Text requirement of section 3 is applicable to these

 copies of the Document, then if the Document is less than one half of

 the entire aggregate, the Document's Cover Texts may be placed on

 covers that bracket the Document within the aggregate, or the

 electronic equivalent of covers if the Document is in electronic form.

 Otherwise they must appear on printed covers that bracket the whole

 aggregate.

 8. TRANSLATION

 Translation is considered a kind of modification, so you may

 distribute translations of the Document under the terms of section 4.

 Replacing Invariant Sections with translations requires special

 permission from their copyright holders, but you may include

 translations of some or all Invariant Sections in addition to the

 original versions of these Invariant Sections.  You may include a

 translation of this License, and all the license notices in the

 Document, and any Warranty Disclaimers, provided that you also include

 the original English version of this License and the original versions

 of those notices and disclaimers.  In case of a disagreement between

 the translation and the original version of this License or a notice

 or disclaimer, the original version will prevail.

 If a section in the Document is Entitled "Acknowledgements",

 "Dedications", or "History", the requirement (section 4) to Preserve

 its Title (section 1) will typically require changing the actual

 title.

 9. TERMINATION

 You may not copy, modify, sublicense, or distribute the Document

 except as expressly provided under this License.  Any attempt

 otherwise to copy, modify, sublicense, or distribute it is void, and

 will automatically terminate your rights under this License.

 However, if you cease all violation of this License, then your license

 from a particular copyright holder is reinstated (a) provisionally,

 unless and until the copyright holder explicitly and finally

 terminates your license, and (b) permanently, if the copyright holder

 fails to notify you of the violation by some reasonable means prior to

 60 days after the cessation.

 Moreover, your license from a particular copyright holder is

 reinstated permanently if the copyright holder notifies you of the

 violation by some reasonable means, this is the first time you have

 received notice of violation of this License (for any work) from that

 copyright holder, and you cure the violation prior to 30 days after

 your receipt of the notice.

 Termination of your rights under this section does not terminate the

 licenses of parties who have received copies or rights from you under

 this License.  If your rights have been terminated and not permanently

 reinstated, receipt of a copy of some or all of the same material does

 not give you any rights to use it.

 10. FUTURE REVISIONS OF THIS LICENSE

 The Free Software Foundation may publish new, revised versions of the

 GNU Free Documentation License from time to time.  Such new versions

 will be similar in spirit to the present version, but may differ in

 detail to address new problems or concerns.  See

 http://www.gnu.org/copyleft/.

 Each version of the License is given a distinguishing version number.

 If the Document specifies that a particular numbered version of this

 License "or any later version" applies to it, you have the option of

 following the terms and conditions either of that specified version or

 of any later version that has been published (not as a draft) by the

 Free Software Foundation.  If the Document does not specify a version

 number of this License, you may choose any version ever published (not

 as a draft) by the Free Software Foundation.  If the Document

 specifies that a proxy can decide which future versions of this

 License can be used, that proxy's public statement of acceptance of a

 version permanently authorizes you to choose that version for the

 Document.

 11. RELICENSING

 "Massive Multiauthor Collaboration Site" (or "MMC Site") means any

 World Wide Web server that publishes copyrightable works and also

 provides prominent facilities for anybody to edit those works.  A

 public wiki that anybody can edit is an example of such a server.  A

 "Massive Multiauthor Collaboration" (or "MMC") contained in the site

 means any set of copyrightable works thus published on the MMC site.

 "CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0 

 license published by Creative Commons Corporation, a not-for-profit 

 corporation with a principal place of business in San Francisco, 

 California, as well as future copyleft versions of that license 

 published by that same organization.

 "Incorporate" means to publish or republish a Document, in whole or in 

 part, as part of another Document.

 An MMC is "eligible for relicensing" if it is licensed under this 

 License, and if all works that were first published under this License 

 somewhere other than this MMC, and subsequently incorporated in whole or 

 in part into the MMC, (1) had no cover texts or invariant sections, and 

 (2) were thus incorporated prior to November 1, 2008.

 The operator of an MMC Site may republish an MMC contained in the site

 under CC-BY-SA on the same site at any time before August 1, 2009,

 provided the MMC is eligible for relicensing.

 ADDENDUM: How to use this License for your documents

 To use this License in a document you have written, include a copy of

 the License in the document and put the following copyright and

 license notices just after the title page:

     Copyright (c)  YEAR  YOUR NAME.

     Permission is granted to copy, distribute and/or modify this document

     under the terms of the GNU Free Documentation License, Version 1.3

     or any later version published by the Free Software Foundation;

     with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.

     A copy of the license is included in the section entitled "GNU

     Free Documentation License".

 If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,

 replace the "with...Texts." line with this:

     with the Invariant Sections being LIST THEIR TITLES, with the

     Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.

 If you have Invariant Sections without Cover Texts, or some other

 combination of the three, merge those two alternatives to suit the

 situation.

 If your document contains nontrivial examples of program code, we

 recommend releasing these examples in parallel under your choice of

 free software license, such as the GNU General Public License,

 to permit their use in free software.