Bring in Power Menu

Summary:
-- add WRITE_SECURE_SETTINGS and become android.uid.system
-- misc. little things that triggered my OCD
-- Kevin, this is gonna be fun!

Test Plan: Depends on D218

Reviewers: synergy, anders3408, jriordan001, raymanfx, donald.munn

Differential Revision: http://review.codefirex.com/D219