Fix SystemUI memory leaks on theme changes.

ContentObserver and BroadcastReceiver instances were dangling after the
status bar was recreated.

Change-Id: I0ef7ef134029e5deec066d405545b8d9ec58d76b

Conflicts:

	packages/SystemUI/src/com/android/systemui/quicksettings/BatteryTile.java
	packages/SystemUI/src/com/android/systemui/quicksettings/DockBatteryTile.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/QuickSettingsController.java
	packages/SystemUI/src/com/android/systemui/statusbar/policy/BatteryController.java
	packages/SystemUI/src/com/android/systemui/statusbar/policy/Clock.java
	packages/SystemUI/src/com/android/systemui/statusbar/policy/DockBatteryController.java