KAZ-27: update spec
KAZ-30: add status_req and status_resp for conferences
KAZ-30: add the status crossbar api for conferences
KAZ-31: add mute and unmute APIs
KAZ-32: add deaf and undeaf APIs
KAZ-40: add kick API

Access via:
/conferences/{conf_id}/{action}?participant_id=N
KAZ-27: send conf command response
KAZ-27: change conf command APIs to:

/conferences/{conf_id}/{action}/{participant_id}
KAZ-27: update spec for content types
KAZ-27: update some function calls and specs
KAZ-27: use call id as participant identifier
KAZ-27: allow participant id or callid, and find participant id by callid