Lockscreen Notifications: rewrite add notification logic

There were some problems with notifications getting replaced while the user was currently dragging them.
This commit should fix that by always waiting until animations and user input are finished before replacing a notification view.

Change-Id: I6821a253e8620d1579e6e1dfa0e0d4571ae1af3d

Conflicts:

	packages/Keyguard/src/com/android/keyguard/NotificationHostView.java