Incorporate fixes from QQmlAnimationTimer into QAnimationTimer.

Incorporates animation timer fixes in:
  * 7da483bfbefcaabb1dbbf3e2f1d5b5f7aadc3b06
  * b02eeeee586abe343b8866385c1327ac009b3ef0
  * 59d5c5cf555a51cd7559cea197a198ef3a792614
from qtdeclarative.

With these changes, we no longer need to call updateAnimationTimers
in QUnifiedTimer::startTimers.

Change-Id: Ic24501cfdc3cb572bd891d84f684f11c3bef1b50
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>