[GATE-115] If a special flag is sent during registration, we don't put the transport in the user's roster.
[GATE-116] If you are registered with the transport, disco info now indicates as such.
[GATE-117] Presence for the transport is always sent on to the client (if a session is active)
Legacy mode and non-persistent transport items are now extinct.

git-svn-id: http://svn.igniterealtime.org/svn/repos/wildfire/trunk/src/plugins/gateway@6013 b35dd754-fafc-0310-a699-88a17e54d16e