Move to vendor overlay option
SystemUI: Status bar clock - fixes

Squashed:
SystemUI: Ensure that the Clock is actually enabled in IconMerger https://github.com/SlimRoms/frameworks_base/commit/42393f259f08535b9fdab98462245830141a299a

Also some fixes from:
https://github.com/SlimRoms/frameworks_base/commit/acdbf3043fcf9c8e4559cb77c81a0249682ba746

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

Change-Id: I7a37a6ae8f9bad0f265119af05dc20cf21cd6890

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