sip_session: add messages for StartRecording/StopRecording

darcs-hash:20090408124039-b2873-52ec90100ff76ba1dbc49206240935066c9b43fe
Fixed sip_register to ignore error for already stopped reactor

Ignore-this: 4a03a07b422c2bac51e3641426e604e4

darcs-hash:20090408134756-1e3d8-e5a292d19ee6a4324606e6c08cca16d9c85fd582