Version Control With Subversion Source

Fix markup so that the foreword validates. Also, the gui* tags come
out totally munged in the PDF output, so turn those into something
more... conventional.

* doc/book/book/foreword.xml: Markup/validation fixes.

Bring svnlook into 2004.

* doc/book/book/ch09.xml: Finish updating svnlook documentation.

Some book tweaks:

* doc/book/book/ch05.xml: Fix typo.

* doc/book/book/ch06.xml: Remove stuttered comma.

* doc/book/book/ch08.xml:
- Add missing word "to".
- Use the word "custom" instead of "proprietary" to describe the
ra_svn protocol, and modernize the description of Subversion's
use of WebDAV, both after consultation with Mike.
- In the "Effective Pool Usage" example, actually clear the pool
at the top of the loop, like the comment says, and destroy the
subpool immediately after the loop, which is what most of our
code does.
- Add slashes to the ends of some URLs.

* doc/book/book/ch05.xml: It's the users list, not the developers list.

* doc/book/book/ch04.xml: Fix typo.

* doc/book/book/ch04.xml
(Copying Changes Between Branches): Tweak wording to avoid a
misleading implication. In the example, it was the change that
was copied, not the file containing the change.

* doc/book/book/ch04.xml: Add missing verb.

Artem Egorkine in IRC points out that it's "foreword", not "forword".
I plead corruption by the German.

* doc/book/book/foreword.xml: Replace 'forword.xml', adjust internally.

* doc/book/book/book.xml: Adjust.

"Would you like anything to drink?" "I'll just have some Meta Tea, thank you."

* doc/book/book/ch01.xml: Fix transposed words.

Write forword to book, as requested by Those In Charge:

* doc/book/book/forword.xml: New file.
* doc/book/book/book.xml: Include it.