LockScreen: Option to hide initial page hints (1/2)

This will add an option to hide the initial page hints
that are shown left and right when the device is turned on.

Change-Id: Id4f29f7cfbaca6b4dd91f0b2de2b8195a966259b
Signed-off-by: Dirk Rettschlag <dirk.rettschlag@gmail.com>

Conflicts:
	core/java/android/provider/Settings.java
	policy/src/com/android/internal/policy/impl/keyguard/KeyguardWidgetPager.java