new arcTo parameters

While looking through the new spec, I noticed that arcTo now takes 2
optional commands: RadiusY and rotation.

This is great because it allows more control over the shape of the drawn
arc and brings the functionality closer to SVG [1].



SVG has 2 more parameters that give you even more control (see the spec for
details). Would it make sense to add those as well?



Rik



1: http://www.w3.org/TR/SVG/paths.html#PathDataEllipticalArcCommands