Settings: Port hardware key rebinding
 squahsed commit of cherry picks from:

Cyanogenmod:
   Settings: Forward port Hardware key custom rebinding (2/2) 607bdae

SlimRoms:
   Settings: More options added to hardware key rebinding (2/2) f0e133f
   Settings: Add Home/Back buttons available for rebinding (2/2) 6588501

removed code for hardware key expanded desktop actions
removed code for hardware key notification shade toggle
Merge branch 'jb4.3' of github.com:TEAM-Gummy/android_packages_apps_Settings into jb4.3