radial gradient gets lost

[try-ruby]

Hello,
thanks for this great library! I was successful with several drawings. Unfortunately, I'm stuck with a circle, having a radial gradient as in the following example. Please help. Thanks!

var paper = Raphael( "foo-container", 100, 100 );
var circle = paper.circle(150, 40, 30).attr('fill', 'r(0.25, 0.5)#000-#fff');
var svgString = paper.toSVG();
document.getElementById('bar-container').innerHTML = svgString;

[AliasIO]

Gradients and dashed strokes aren't currently supported. If you want to give this a go yourself I'm happy to merge your changes in.