LockScreen: allow hardware key longpress to put device to sleep

Change-Id: I251e72cda94f88de3715d818ba62e796e3b2ccd0
Camera button support (2/2)

Add new bitmask for Camera button and options to rebind
its functionality.

Change-Id: I803d3b99adcdd6f2d9de15091709fc8c783ed5de
Settings: Use meaningful titles for gamma controls

There is good anecdotal evidence that the values we modify relate
to specific modifications (contrast, brightness, saturation and the
like) of the display, this change allows us to define descriptive
headings.

Change-Id: I2935924fd86f13e95b919e7b7c7a0bc931ac50bb
Add missing variables for camera button handling

Change-Id: I40abd4344800e8cf61285923cc1fac9ba39d652c