Version Control With Subversion Source

Finish issue #137 ("1.7 change: svn diff now shows textual property
changes in unidiff format, except for svn:mergeinfo properties").

* en/book/ch03-advanced-topics.xml
(svn.advanced.props.workflow): Update sample output from 'svn diff',
and massage wording about how properties are represented to include
a mention of 'svn patch' and its utility here.

* en/book/ch09-reference.xml
(svn.ref.svn.c.patch): New placeholder section.

* en/book/ch06-server-configuration.xml
(Server Optimization): New section.

* en/book/ch09-reference.xml
Document the new --cache-fulltexts, --cache-txdeltas, --compression,
--memory-cache-size, --prefer-ipv6, and --quiet options to svnserve.

Merge from ^/trunk/en r4054, which just added some missing divider
comment lines.

Add missing divider lines.

Merge from ^/trunk/en r4052, which adds a note in the reference about
'svn update --set-depth' (with a pointer to the Sparse Directories
section).

* en/book/ch09-reference.xml
Note that 'svn update --set-depth' is the primary way that sparse
directories are managed, and point to that book section.

* en/book/ch09-reference.xml
More reference updates for Subversion 1.7.

Merge the relevant subset of r4049 from ^/trunk/en (the swapping of
some sections in Chapter 2), just to prevent future spurious merge
conflicts.

This covers:
Issue 118: ("1.7 change: New 'svn log --diff' option")
Issue 119: ("1.7 change: New 'svn diff --git' option.")

* en/book/ch02-basic-usage.xml
Move the coverage of 'svn log' to after 'svn diff', and then call
out the special 'svn log --diff' functionality as a handy shortcut.

* en/book/ch09-reference.xml
Document the following:
svn diff --internal-diff
svn diff --git
svn diff --show-copies-as-adds
svn log --depth
svn log --diff
svn log --diff-cmd
svn log --extensions
svn log --internal-diff

Finish issue #144 ("1.7 change: HTTPv2").

* en/book/appc-webdav.xml
Mention HTTPv2 as a reality, not a future possibility.