Add hardware tunables (gamma, color, vibration strength).

Change-Id: I44e3e4e6cb444498a7c56048618cd92a0e2b8e59

Remove 'More device settings' menu

Change-Id: I86cd84f6f6c408b26c04d92529e9a031c4fed1f7

Settings: Add default value for display color control (2/2)

Change-Id: I50b684abe504c21ef49492f99b18873d75509697

DisplayColor: Properly handle a minValue

* Previously setting anything as a minValue would cause the
  percentages to get out of whack. For instance, setting it to 35
  would cause the maximum percentage to climb above 100% as well
  as still allowing the value to be set lower than the min.
* This makes the maximum for the slider the max value minus the min
  (so we get the proper spread for min to max) and then adds the min
  back on before setting so we can't possibly go below the min.

Change-Id: I8dcdc422f54847940351fae10c74af6301d1e1be

Cleanup.

Now that button and keyboard backlight don't use the HW framework
anymore, there's no point in having an abstraction for a single use case.

Change-Id: Ib66b2a29a105d53e3ba4273abb06977b132c1fc8