Settings: Add support for variable size pattern lockscreen (Part 2/2)

Part 1: http://review.cyanogenmod.org/#/c/28533/

Port of: http://review.cyanogenmod.org/#/c/20614/

Add a menu to choose the pattern unlock screen size (currently 3x3 to 6x6)
Default size is specified in the frameworks

Change-Id: I5e3d1f8b19b7f5017c854ab9d28b459214f00949

Conflicts:
	src/com/android/settings/ChooseLockGeneric.java
	src/com/android/settings/ChooseLockPatternTutorial.java