frameworks: Custom System Animations

Allows setting of some system animations.

Current List:

Activity Open
Activity Close
Task Open
Task Close
Task Move to front
Task Move to back
Window Open
Window Close
Window Insta Open
Window Insta Close

Duration Controls

Prevent overridePendingTransition option

Change-Id: Id360abe158d36ab85c1c0d0103428d4a8867e70c
GlobalAction dialog ref not set to null

When a GlobalAction dialog is dismissed when screen goes into
sleep the reference mDialog is not set to null. Next time the
long presses power button and brings up the GlobalAction dialog
the old reference still exist and we try to dismiss the dialog
again even if it does not exist.

The dialog reference in this case holds on to the dialog object
using more memory than neccesary, and in rare cases we might get
a crash when the dialog object is dissmissed the second time.

Change-Id: I44ef1c385d90777e8f6dd9fe111eb3d9b0d3cf3f