Version Control With Subversion Source

Fix reference matter for --depth, and describe --set-depth.

Name tweak. (This is the guy who wrote "The Railway Series", on which the
whole of Thomas the Tank Engine and his friends are based, by the way.)

* src/en/book/ch03-advanced-topics.xml
(Sparse Directories): Track Subversion change recently made, where
one uses 'svn update --set-depth' instead of 'svn update --depth'
to tweak ambient depth. Also, lose the equal signs (=) in the
demonstrated commandlines -- I can't stand those things.

Oops. Fix a spelling error.

Update my acknowledgments.

* ch04-branching-and-merging.xml: output tweaks from Arfrever Frehtes Taifersar Arahesis <arfrever.fta@...>

Jan. 7, 2008 drop of 1.5 book to O'Reilly.

* src/en/book/ch03-advanced-topics.xml
With much love to Fitz for a good effort, pretty much completely
rewrite the Sparse Directories section.

* src/en/book/ch04-branching-and-merging.xml
Move a tip about how to see the svn:mergeinfo diffs here (from the
Sparse Directories section).

Updated list of assigned tasks.

Update a screen capture of 'svn help import'.