Last App Toggle (for PIE)

Conflicts:
	core/java/android/provider/Settings.java
	packages/SystemUI/src/com/android/systemui/statusbar/NavigationBarView.java
	packages/SystemUI/src/com/android/systemui/statusbar/PieControl.java
	packages/SystemUI/src/com/android/systemui/statusbar/PieControlPanel.java
	packages/SystemUI/src/com/android/systemui/statusbar/view/PieMenu.java