Add statusbar and navigation bar opacity slider

  Patch Set 3: Rebase before merge

Change-Id: I861ed8f006cc42bba09890983df7e72d9bf0c472
Signed-off-by: Roman Birg <romanbirg@gmail.com>

Conflicts:
	res/values/strings.xml
	res/xml/prefs_ui.xml
	src/com/aokp/romcontrol/fragments/Navbar.java
	src/com/aokp/romcontrol/fragments/UserInterface.java