Added missing context attribute to MediaStreamDidFail notification

Ignore-this: 41e836b23628a4ec8b98a49c867a9979

darcs-hash:20130916135206-b22ec-c309109fa45230bf077a0b0680d3c910d410f9d0
Fixed memory leak by initializing the handler after the stream initialized

Ignore-this: 893593c2d4c80b24677942f80a30f310

darcs-hash:20130916143934-b22ec-1bceddeffce36c73ed517df719ef99614bb2b19c
Moved AudioConference to audio module

Ignore-this: b4d19fd39102eb78397ee096b51da35d

darcs-hash:20130917143107-56b4d-752bc41cceb3cd0012307743ffa0787106068425