(UpdateManager) Fire animation notifications ONLY when scene is actually updated

(UpdateManager) Fire animation notifications ONLY when scene is actually updated

[problem]     Timing problem where animation finsihed callbacks are emitted before the scene has
              been updated.
[cause]       We add messages to the event-queue before we've updated the scene. The queues can
              be swapped while we're still updating and the finished callback can be then fired.
              Any attempt to get current values in this callback will be from the previous frame.
[solution]    Delay adding animation-finished messages to the queue till just before update ends.

Change-Id: I3c610e5139e1bfe32873cf3f85474ab7d61ed343
Signed-off-by: Adeel Kazmi <adeel.kazmi@samsung.com>