use SettingsObserver to update value of auto expand statusbar

Change-Id: I707f4a61a83a9b471f3711b7f56d4ac8bc339ec1
lockscreen: when using an settings observer we still must load them on startup

Change-Id: Ib913ad4b4bd55d0a794fe505bd1ae5d2341d6c66
FW: rework statusbar hiding again [1/2]

Change-Id: I103fe9e5473ce16b5c977f051ecbd510dfdaefa7

Conflicts:
	core/java/android/app/Activity.java
	core/java/android/provider/Settings.java
	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java