Log Message:
Update to r3987 (0.16).
User-visible changes:
 * new 'svn cat' subcommand
 * new --revprop flag to access revision props, -r for versioned props (#943)
 * new "compression" runtime option in ~/.subversion/config
 * svnadmin/svnlook now use help system, and some subcommands deleted or moved.
 * tool changes: [not installed by the package]
    - new svnshell.py tool
    - new mirror_dir_through_svn.cgi script
    - new svn_load_dirs.pl features
    - updates to vc-svn.el
 * --message-encoding is now just --encoding, and affects svn: propvals too.
 * major rewrites of chapters 3, 4, 5 of the Subversion Book.
As well as lots of bugfixes, of course.