Creating connections for conference event package participants.

- Add "getPrimaryConnection" method to conferences.  This method is used
to get the primary connection from which the conference state will be
retrieved.  In the case of IMS we look for the connection which is marked
as multiparty.
- Modify telephony conference controller to create participant
connections and add them to the conference.

Bug: 18057361
Change-Id: I585878aae73594057f284044c4da736694bf9a76
3 files changed