Fix to mute/unmute properly while adding a call

Call setMuteInternal instead of setMute while adding
call to an existing active call.

Change-Id: I245f966c6929b5d1a92b2b7dff1f9e79e2a8d04a
CRs-Fixed: 650135
Fix issue that phone would crash when PLMN search

NetworkSetting apk is only installed on debug build, before calling it,
check it whether exists in the system; if true, use the intent of the
NetworkSetting activity instead.

Change-Id: Ib139874e5f2ffbc20ceaba4f83491f5ce0939353
CRs-Fixed: 659685
Fix crash during back to back emergency calls.

Phone process crashes with RuntimeException while
unregister receiver because the receiver is not
registered.

Move code of register receiver at onCreate() to be
sure that receiver will register when call through
bindService() and startService() both the cases.

Add null checks to avoid null pointer exception in
onDestroy() of EmergencyCallbackModeService.

Change-Id: If73bffe251b9f8f64973bcac7399a903bc2183e6
CRs-Fixed: 641312
Delay setting of active subscription

In case of MT call, delay setting of active subscription till we send
onIncoming to InCallUI. Until onIncoming comes, there is no MT call
in IncallUI call map, hence active sub shouldn't be set much earlier than
sending onIncoming() in order to avoid timing issues.

Change-Id: I7a6ff5bed017d51e540f207093565310e6e9e511
CRs-Fixed: 655859