settings: Add support for SRE

 * Add support for sunlight readability enhancement
 * Optionally depends on adaptive backlight, depending on HAL

Change-Id: I9ca388ffd68080f0e497edb81d5f8616c194ea1d
Screen off gestures: Show options only on supported devices

Change-Id: Idac21e8356a75b31d94e0a600d97590b95a55777
Merge pull request #27 from LiquidSmooth/kitkat3

marge pull request