[2/2] illusion settings: add custom hardware button mapping

Possible mapping

 0 - Nothing
 1 - Menu
 2 - App-switch
 3 - Search
 4 - Voice search
 5 - In-app search
 6 - home
 7 - back
 8 - toggle last app
 9 - kill app

PS7: Fully working

Change-Id: I3b8b3bbd31b416d0952acd1f9a86cdd28a8002e5

Conflicts:
	res/values/arrays.xml
	res/values/strings.xml
	res/xml/preference_headers.xml
 Status bar brightness control (From Omni)

Change-Id: I371c914199929b8231a0d7e448eeda321e92b029
Fix import and package derps

Change-Id: I16e032bb53a1da86e4d06a16930f50c11c3836bc