SystemUI: Status bar clock
- fixes This commit fixes:
- no overlapping
more from status bar icons on center clock.
  The width depending on what the user has setuped (date and clock) is
exactly meassured now - do not start animations if they are not needed
- reduce settings provider calls
- a bit cleanup

fix from slimroms

Change-Id: Ib0aa13ef26adf092b921b98652173a28e08cdbdb