ListView and GridView can now be assigned transitions to be run when:
    - Populating the view (when initially setting the model / resetting)
    - Adding items
    - Removing items
    - Moving items

The ViewTransition attached object can be used from within a transition
declaration to access various information about the items that are
being transitioned.

Task-number: QTBUG-21504

Change-Id: Ie5c75ea511c8b15acc3f06fccf19abe34d3677f9
Reviewed-by: Martin Jones <martin.jones@nokia.com>