Lockscreen Notifications: dismiss all button, improve animations, cleanup

Conflicts:
	core/java/com/android/internal/statusbar/IStatusBar.aidl
	packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java
Lockscreen Notifications: fix show/hide of show all button

& fix endless SystemUI FC when SystemUI is killed
Lockscreen Notifications: fix NPE