AutoHide Statusbar

Ported from https://github.com/SlimRoms/frameworks_base/commit/3982e50efb490f01a01c74bc6b190ecddf7c1480
and taken from https://github.com/BeerGang/android_frameworks_base/commit/b81079f2adcc816a976798ffbf78e91e26ef7e03

Change-Id: Icaace6c54d60cad82bd24bb40fba90969ab18b5f

Conflicts:

	core/java/android/app/Activity.java
	core/java/android/provider/Settings.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java
	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java

Conflicts:

	core/java/android/provider/Settings.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java
	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java