Version Control With Subversion Source

More Subversion book work. This time, we take on Chapter 5!

* doc/book/TODO:
Remove the relevant TODOs.

* doc/book/book/ch05.xml
Rework some parts of this chapter. Add a new "Berkeley DB" section
under "Repository Basics", add a placeholder for "svndumpfilter"
documentation, and do a bunch of other juggling around of stuffs.

* doc/book/book/ch09.xml
Tracking a moving xref across the plains of Rohan.

Fixup the documentation about restoring default configuration values.

* doc/book/book/ch07.xml
(Configuration Area Layout): Make the appropriate edits.

* doc/book/TODO:
Remove the relevant TODO.

Reorganize and expand chapter 4 a bit. ("Branching and Merging")

* ch04.xml: make the need for "manual merge tracking" clearer and more
explicit. create a new "use cases" section for merging which
demonstrates (a) repeated merging of one branch to another, (b)
undoing a change, (c) resurrecting deleted things.

* ch06.xml: implement a rewording suggestion from Blair.

* REVIEW: remove the suggestion.

* doc/book/TODO: notating another clarification to make.

Remove possibly confusing language about licenses from the book:

* doc/book/book/ch01.xml: Daniel Rall pointed out that "Apache"
doesn't necessarily imply software to most people. Rather than
expand to clarify, it seems better to just not mention Apache/BSD.

* doc/book/book/ch01.xml: Cite book by title, as requested by cmpilato.

Rewrite the history section of the book, as threatened^H^H^H promised:

* doc/book/book/ch01.xml
(Subversion's History): Convert tone of mystical inevitability to
one of contingent activity.

* doc/book/TODO: updating some notes.

Next stop... is 1.0

The doors open on the left... at 1.0

There is no smoking, littering, or radio playing on the build train.

* doc/book/book/ch06.xml: Fix typo.

* book/ch06.xml: clarify misleading text around apache Location block.