SRVCC Conference with Mid Call Enabled.

1. Add support for SRVCC with more than 3 participants.

There is a max limit of 7 connections in GsmCallTracker. If RIL
reports call id greater than 7, it will be ignored while polling in
call tracker. Because of this, in case of SRVCC with more than 3
participants, call ids greater than 7 are getting dropped from UI.
Fix this by increasing the max connections limit to accomodate call
IDs after SRVCC.

2. Add support for SRVCC Conference with greater than 3 participants

The phantom call mechanism that is used to notify the participants
of conference call during SRVCC, notifies only the last unknown
connection. During SRVCC conference call, all the participants
after the first are using the phantom call mechanism and hence
each unknown connection resulting should have a seperate notify
from frameworks.

3. Add support for using the CS connection address during SRVCC

Updated the values that are migrated from handover connection.
Some fields which have an updated value from the driver call list
are used directly instead of migrating their values from handover
Ims Connection.

4. IMS: Fix for duplicate registrants during SRVCC.

Currently CallManager registers for different phone states
with Gsm and Ims phone. But while handling the UNSOL SRVCC state
change the migrate function in PhoneBase, does no check for the
duplicate registrants and copies all the ImsPhone registrants to
GsmPhone.

Fix: Dont migrate the registrants from ImsPhone to GsmPhone if
CallManager has already registered with default phone for these
registrants.

Change-Id: I67ac7d7156e4d0dec8c66059263f0e29a6337c66