svg_circle_element: implement get_exents.
svg_circle_element: implement get_exents.

gjtorikian/lasem,wavewave/lasem,janmarthedal/mathml2svg,gjtorikian/lasem,gjtorikian/lasem,gjtorikian/lasem,wavewave/lasem,janmarthedal/mathml2svg,wavewave/lasem,janmarthedal/mathml2svg,wavewave/lasem,janmarthedal/mathml2svg