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
Keep InCallUI in memory (1/3)

In lower end devices, startup of the InCallUI process can take
up to 10 seconds when the device is busy, which prevents the user
from taking the call. Keep the process in memory like previous
versions where they are a part of Phone.apk.

This converts InCallUI into a dummy apk with the persistent
attribute set to true and allows the activity from Dialer.apk,
which uses the com.android.incallui process to be loaded into the
persistent process.

Change-Id: Idfb7fa760eacc8d6e46d50ce682fb06c0acfc8f4

Conflicts:

	AndroidManifest.xml