fix unstable VRectangle / VCircle contains calculation.
see issue #322
For specific combinations of rectangles and circles, the generic
containsShape() method which builds on the AWT
hangs in an endless loop. This is most likely rooted in the problem that a circle is approximated by bezier curves in the
Area class and this causes numerical instabilities.
This fix only is implemented in the
VRectangle class for now. Other
VShape objects still use the old (numerical instable)
containsShape implementation (which is based on AWT's