Allow hardware overflow key to be show by default.

Currently this is controlled by a system setting, but there is no way to
set a default value for the system setting. This is very useful to have
for devices that have no hardware menu key.

Change-Id: I94212def19d3e2224d79d3a89e1e2d3b2883da21
Lockscreen : Add custom background overlay

Adds an overlay on top of custom images/colors to better match
stock appearance.

https://jira.cyanogenmod.org/browse/CYAN-1280

Change-Id: I1210d208de912e7f6a1941284f1fe1ff0776ab48