Add Rpc in Call control.

Add several Rpcs for call control, including:
Disconnect call by id;
Split call from conference by id;
Merge call to conference by id;
Hold call by id;
Unhold call by id.
Mix minor bug in telecomPhoneGetCallIds:
if no ongoing call, this Rpc call will cause null exception.

Change-Id: Iea75aac82cf0ef95a8976c0ab6655a5500c91f0f
1 file changed