"auto" on rx/ry

The rx and ry properties of "<rect>" and "<ellipse>" can be set to the "auto", which means that the value of the other property is used.

The rx and ry properties of "<rect>" and "<ellipse>" can be set to the "auto", which means that the value of the other property is used.

This is handled by the CalculateRadiusMaybeAuto function.