Lockscreen targets: more unification

Use shared method to derive drawable inset and make the rounded
corners for icon files also display when adding the target initially.

Change-Id: I98ea3e522c4c6240f08e11007d53509a3d2c15f8
Fix removal of backlight settings

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: I118e667b306a5a1e50d593f3f18828b7a921a511
Merge "Fix removal of backlight settings" into cm-10.2
Merge "Lockscreen targets: more unification" into cm-10.2
Merge remote-tracking branch 'upstream/cm-10.2' into cm-10.2