Add AudioStream.recorder property and remove obsolete ones

Ignore-this: 66e0a7d612ec0cc687c653c915c154ab

darcs-hash:20140306170609-56b4d-17aaf0d6b8c11a3ddb492be2156ce697072d3a88
Fixed cancel_proposal when no streams were proposed

Ignore-this: 25d9ae9b09288af29d42ecaec467195b

darcs-hash:20140307094423-56b4d-35b232a7c72b24a521dd391128b97a40d8127580