Camera: Handle keys only while in app

Thanks to Lars Greiss (SlimRoms)

Change-Id: I63f757d25260fba4683f494f8b4daf178a2b4e13

Conflicts:
	src/com/android/camera/CameraActivity.java
	src/com/android/camera/PhotoModule.java
	src/com/android/camera/WideAnglePanoramaModule.java