Added proposed_streams attribute to SIPSessionGotAcceptProposal

Ignore-this: 4986edba6af67fe285ae61804a5ead3

darcs-hash:20100609125314-1e3d8-f1b3d215ae7bc66d48fba64c8f87649c6bbfa86f
Made filename argument of start_recording mandatory

Ignore-this: 326df0f0d548756ab21090f6f2ba94c0

darcs-hash:20100609135342-1e3d8-ed9d6ee5ee50282d6992548c0016019e97829ab6