Version Control With Subversion Source

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