Comment 4 for bug 202540

I don't have a current bzr checkout, so this patch is against 0.47 stable (I'm betting that nothing's changed in cubicsuperpath.py since then). I've tested[0] on quite a few shapes and get the results I expect - though I must confess that I'm not 100% sure it's valid SVG. It could use some testing.

[0] only with the 'Add Nodes Extension' so far