Lockscreen options : Camera/widgets toggle

As per https://jira.cyanogenmod.org/browse/CYAN-1243
this commit allows user to control visibility of widgets/camera on lockscreen.

Change-Id: Idab2ff4f058e355a1e5936531d9a264b1fea16a1
Merge "Lockscreen options : Camera/widgets toggle" into cm-10.1