ROMControl: Customizable Softkeys

This allows enabling, and setting of sort and long press options
for softkeys.

Overlay will enable this section as well as let RC know which buttons
the device has.

for testing the section is enabled and so are home, menu, search, and back

If your device doesnt have those buttons just ignore them for now your
users will never see them.

PS2: Add missing drawables

Change-Id: I32c882b97fc341f9f545cf694bd393dfa6f926a3
Signed-off-by: Rohan Mathur <rohanmathur34@gmail.com>
Signed-off-by: Brandon McAnsh <brandon.mcansh@gmail.com>

Conflicts:
	res/xml/preference_headers.xml