settings: lockscreen widgets (2/2)

- This also keeps a lockscreen shortcut option in settings header and also includes a summary in the same

see fb commit for more details

thanks to @kufikugel

Change-Id: Ie612557ccc3e28ece3d3c726376c2ddc5c9839b5

Conflicts:
	res/xml/lockscreen_interface_settings.xml
	res/xml/security_settings_chooser.xml
	res/xml/security_settings_password.xml
	res/xml/security_settings_pin.xml
	src/com/android/settings/SecuritySettings.java