Framework : Lockscreen - Customizable shortcuts

Forward port lockscreen shortcuts

Change-Id: Ic3b935df5c0da35f31373d96943e442dc39cf11b
Add back navigation ring customization

Change-Id: Iebe4ec7c2519b85cfd5189d060444764a50f3cf6

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