Density changer from AICP [SQUASHED]

Also contains this from AICP
https://github.com/AICP/packages_apps_Settings/commit/e61b6a62d4cb8acc31c7e9d2d5b1ae440abba1f1

Change-Id: I8828a06b15ed42090bd86797494b46e0e9f97b0b