Update mod_deflate's documentation.

Update mod_deflate's documentation.

Note that this does NOT include the transformation since I can't find a
version of Xerces or Xalan which does not produce major diffs to what
we have checked in.  So, we need to standardize on a set of jars -
otherwise, if I were to commit what I get when running build.sh, it'd be
massive.  (I'd suggest a tarball of jars on the docs-project site or even
in http://httpd.apache.org/dev/dist somewhere.)

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@94986 13f79535-47bb-0310-9956-ffa450edef68