Settings: Security: implement a pin keypad shuffler [2/2]

this is to further prevent people using the tablet guessing your pin based on fingerprints left on the screen
example of the expected outcome - https://www.dropbox.com/sh/r3xb2q53ksaqni9/Oz1Eu8Dm7O

PatchSet:
- fix checkbox was wrong assigned
- enable only for PIN Password lock
- small cleanup of old code

PatchSet:
- cleanup

PatchSet:
- add modes.....disabled/always/on request

Change-Id: Ic44d7bd593033843691ecd553d1decb7c15ffd68

Conflicts:
	src/com/android/settings/SecuritySettings.java

Conflicts:
	res/values/cr_strings.xml