Updates to work with shared groups.  Couple of other minor tweaks.  Something is still 'off' with the rosters, especially Yahoo.  More work to be done.

git-svn-id: http://svn.igniterealtime.org/svn/repos/wildfire/trunk/src/plugins/gateway@4981 b35dd754-fafc-0310-a699-88a17e54d16e