Settings: Make Safe headset volume handling user configurable (2 of 2)

I am lazy I admit.

Change-Id: Ib14852b90ab02b8750725de0ab15888ad0f2ab16
Add option for switching between UMS and MTP/PTP mode. (2/2)

Change-Id: I6cf50a41a9a82e40e702f5231ce663636c149613

This adds support for switching between UMS and MTP/PTP.
Settings part (this part) adds option in USB settings (statusbar/notification drawer) for enabling UMS,
and adds setting in Storage menu to enable / disable UMS, this since the USB settings page disappears when enabling UMS.

It's only porting this http://review.cyanogenmod.org/#/c/21115/

Conflicts:
	res/values/strings.xml
Use ROMControl Performance Control fragment

Change-Id: I6a119a83d61330f5129a35533e2339484a68f7e2
Add back backlight curve adjustment.

Patch set 1-8: Initial commits
Patch set 9  : Shortened strings to better fit Design Guidelines

Change-Id: I1eb370f8911d1c92ef06e553cc1c1be81e83cb95

Conflicts:
	res/values/strings.xml
Add back Quiet Hours Activity

Change-Id: I96255e76285b38fd65b09e1170d0a3d7462bc11c
Some post-merge cleanup for automatic brightness adjustment

- Remove some unused strings
- Use (device-dependant) minimum brightness level (as calculated by
  DisplayPowerController) as '0%' instead of the actual value 0.

Change-Id: I79123d2421c9ab35fa0f1808d82d785463e8fbaa
Notification PowerWidget support

Change-Id: Id65d33d3acc35913834235b486446942ec6bb77c