added support for microphone and speaker.

Ignore-this: e07eb81c32ed049f91d59db427aa6

I will add support for choosing codec later.

darcs-hash:20140701133406-c21fe-f1661705938d4072dff71ce2d3785b45b2cb1687
added param to set audio codec

Ignore-this: e89133b24a82b09c9c5af1ec26061339

only pcm and mp3 are supported at the moment.

darcs-hash:20140701134332-c21fe-9f3356ad146bd056352a6680251bf3cbda73492c