animation and bubbling
Due to SMIL2 the repeatEvent bubbles not, due to SVGT1.2 it bubbles
(what is not really useful).
The xlink:href of the animation element on the right is animated with
several repeats.
This repeatEvent of animate and 0s are used to start the fill animation
of the rectangle top left.
The fill animation of the rectangle bottom left is started using the
the repeatEvent of the animation element.
If the repeatEvent bubbles, the fill animations on the left are the same,
if not, the bottom left fill animations starts only once at 0s.