Settings menu cleanup

- Superuser header moved below Developer Options
- Having two performance options makes the menu clunky. So I took out
the CM one as the AOKP one offers more functionality over CM's one
- Moved toolbar settings to System

Compiled and works fine for me, looks much less cluttered as well.
https://www.dropbox.com/s/z6u1z7r0g799s5z/2013-03-24%2018.06.35.png
https://www.dropbox.com/s/x975o6l8nm3fmuf/2013-03-24%2018.06.45.png