Add center clock (1/2)

Patch Set 2:
  Add super_status_bar_center_clock layout for sw600dp devices

Change-Id: Ibda358eac82e8f567d7e130c0f7d63b73d398cf5

Conflicts:
	core/java/android/provider/Settings.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java