Base: Allow unregister Callback and Controller

Battery, Bluetooth, Network, Location controller
always set callback without release them if callback owner is missing

add this method to unregister the callback to prevent memory leak

fix whitespace

Change-Id: I0d6451ddfb681bd5301e7958e20d2462d4a82039
Merge remote branch 'omni/android-4.4' into android-4.4