InCallActivity: consume back key on incoming call screen

Users will not be able to anything if the physical back key is
pressed on the incoming call screen (return to home screen with
nothing responding.)

Forward porting the key consumption from 4.3

Change-Id: Iea0734852bac7ca5a25e19ec9d9ee7c80dba6741
InCallUI: add decline and answer  incoming call action on notifications

Add decline and answer call action on notification if an call is incoming. Especially
usefull for call in background feature to have the ability to directly
decline or answer a incoming call. But as well usefull to decline/answer a second call
during one is incomming.

PS:
- found a better way for the answer button

PS:
- fix keep flip action alive
- fix collapse notification shade when answering call
- answer call before starting the UI to do not have
  shown the incall screen for a brief second

PS:
- fix wrong user on sending close system dialogs

Change-Id: I92d8f5a2de74f9877a61c4da4c3eaf2e25230895

Conflicts:
	src/com/android/incallui/InCallPresenter.java
InCallUI: Set Ticker to contact

Display contact/number/confrence
	in notification ticker.

PS2:
Implement Kufikugel's suggestion.
	Incoming call ticker only.

Change-Id: Ie89cceb67aecbf3dd15abd07dc35110f7fddc2f9