* doc/book/book/ch03.xml
(Resolve Conflicts): Explain what happens in the case of a binary
file with a conflict.
* doc/book/book/ch04.xml
(Merge Conflicts): New section explaining "skipped" messages from merge,
how file conflicts can happen, and how merge
uses different conflict fulltext suffixes.
(Common Branching Patterns): New section explaining how "release
branches" and "feature branches" work.
* doc/book/book/ch05.xml
(Hook Scripts): Add tip about hooks running with empty environments.
Mention mailer.py alongside commit-email.pl.
* doc/book/book/ch06.xml
(Overview): Tweak some wording.
(svnserve): Mention that tools exist to run svnserve as win32 service.
* doc/book/TODO: remove to-dones.
