IMS: SRVCC related changes.

1. Telephony: Multiparty srvcc

    Change-Id: Ie689f31d7970ecf3a5008cf1dad450045d0b34db

2. SRVCC: Add support for incoming call SRVCC

    Transfer connections from ringing call to handover call on getting
    Handover Complete notification. This allows for accept to be done
    on the default phone instead of IMS phone after SRVCC. Set the
    state of ImsPhoneCall object to Idle after the transfer.

    Change-Id: I09cfcc9fc99b3ea4b3a4bd332af546bcfae4b679

3. Add support for SRVCC conference call

    Add support for updating the parent of handover connections to
    point to handover call.
    Update status of the handover call object based on the status of
    foreground, background or ringing call.

    Change-Id: Iacd7daa929d0da9a0e020491669165aa42bed144

4. Add support for SRVCC connection clean up in Ims Service

    Added support for SRVCC connections to be cleaned up in the IMS
    Service by calling close opertion on the call session and
    subsequently removing the call session from list of tracked call
    sessions

    Change-Id: I850ab111c884bbe7698810b15d0e9c8bdb10e8c9

5. add null check when add all srvcConnection

    add null check when add all srvcConnection

    Change-Id: I3bc93a301584e7fc16ef5aabf474bd1577402d22

6. IMS/911: Do not clear handover connections on SRVCC COMPLETE

    Even though SRVCC or silent redial is successful, the handover connection
    objects are cleared before migrated to CS domain. Proper checks are added
    NOT to clear the handover connection objects as they are removed as and
    when a new driver call via CS pipe is received and processed.

    Change-Id: I061fa81e651b4c6b6bdea1f1cf0b09dde39fdb4a

7. Add fix for picking correct Handover connection

    A single handover call cannot track both the foreground and
    background call state after handover.

    Added support to go through all the handover connections and
    pick the first match based on the number and if there is no
    match check the state.

    Added support for tracking the state of call associated with
    the connection before handover. This is used to retrieve the
    correct connection based on state.

    Change-Id: Iec87c09523d459998d0880252a71f98eb8e296a2

Bug: 18559588
Change-Id: I0c428b33e09684fc7f33f0abd7f9c0471961ad1f