LockscreenPattern : Toggle dots/error pattern visibility (1/2)

Give user ability to hide error pattern / dots.

Part 2 : http://review.cyanogenmod.com/#/c/21543/

Patchset 2 : Minor formatting

Change-Id: Idda9539b213eb78391b725fcd89ff5d93c8090ce

Conflicts:
	core/java/android/provider/Settings.java