Settings : Add hooks for device specific features

Add support for :

Devices with bluetooth input peripherals
Devices with screen gesture support
Devices with a back touchpad

Change-Id: Iabad460a6d1b0d8bf2e84ace92dea1f6901fb4d0
Merge "Settings : Add hooks for device specific features" into cm-10.2
Merge remote-tracking branch 'upstream/cm-10.2' into cm-10.2