Updated TODO

darcs-hash:20090214014048-1e3d8-864fe7ff4b189d8e7ac5056b4fef84e0e40f3ce2
Fixed default value of trace_sip in sip_audio_session

darcs-hash:20090214020215-1e3d8-6360570bcca6c6a7b4e09e2fb1bf4049ff5e1b3d