Version Control With Subversion Source

* src/en/book/ch09.xml
(svn switch): tweak some wording, add a Warning box explaining when
to use --relocate and when not to.

* src/en/TODO: add some ideas.

Merge and update changes between r1160:1211 from the English book into
the Norwegian version.

* src/nb/TODO
Merged r1208.

* src/nb/LAST_UPDATED
Updated by make sync.

* src/nb/book/appc.xml
Merged r1189.

* src/nb/book/appd.xml
Merged r1208.

* src/nb/book/ch03.xml
Merged and updated r1202.

* src/nb/book/ch04.xml
Merged r1163.

* src/nb/book/ch06.xml
Merged r1186, r1202.

* src/nb/book/ch07.xml
Merged r1203, r1206.

* src/nb/book/images/info.png
* src/nb/book/images/note.png
* src/nb/book/images/warning.png
* src/nb/book/styles.css
Merged r1211.

* src/nb/Makefile
Merged r1205, r1209.

* src/en/book/images/note.png
* src/en/book/images/warning.png
* src/en/book/images/info.png
New transparent-backgrounded PNG versions from Jens Elkner.

* src/en/book/styles.css
Lower-case style names, and make some other little (mostly color) tweaks.

Book Spanish. Translated some paragraphs.

Add an experimental new make target "make valid", as a shortcut way to run
XML validation on the book. It will need further work to be cross-platform.

* en/Makefile: Add "valid" target, runs XML validation.

Appendix D (tools using Subversion) matters.

* en/TODO: Note that Appendix D needs a review.
* en/book/appd.xml: Remove Kwiki. Move Trac to "higher level tools" section.

* tools/bin/find-xsl.py (candidate_xsldirs): Add comments, and Debian's location for
the DocBook XSL stylesheets.

Partially revert r1203, which in part talked about the keyword canonicalization
feature which has been reverted from Subversion.

* en/book/ch07.xml (svn-ch-7-sect-2.3.4): Rewrite wording to preserve good bits of
r1203 whilst removing parts that spoke specifically about canonicalization.
Undo some over-enthusiastic standardization from r1203 - say "abbreviated" not
"also specified" in the HeadURL/URL case.

Move find-xsl.py into the tools/bin directory.

* tools/find-xsl.py: Move...
* tools/bin/find-xsl.py: ...here, and adjust relative path in script.
* en/Makefile (ENSURE_XSL): Adjust to above, and move to more appropriate
location in file.

Book Spanish. Translated 16 paragraphs.