Fix how version number is saved/retrieved. Version is now stored in

VERSION file, which is created in the tarball target.  This is then
installed at /usr/share/monkeysphere/VERSION, and cat'ed when the
version number is requested by the front-end ui.  No more manual
setting of version number required (to avoid future problems, aka
"0.23.1").  This system is also more flexible, as the VERSION file
could potentially hold more info than just the release number.