Bring the baby back: longpress back button to kill the app [1/2]

this old CM baby (made by @rascarlo) is still useful till
kufi does his magic on the navbar :D

Change-Id: Ic8a94679226cc5f575bd670251db978797af96d0
Bring another baby back: longpress recents to go to last app

Thanks again to CM.
Some anim optimizations thanks to Mahdi rom.

Change-Id: Ic09d727a4c74b9c6ca8837991f6f17536deb46a7