Settings: Add support for SRE

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

Change-Id: I8d2cbb8a7dfc164dd3b3301326f20f6f823ce351
Signed-off-by: STELIX <ssspinni@gmail.com>
Merge pull request #22 from CarbonDev/kk

Settings: Add support for SRE