Supershape merging

[marioepsley]

I was trying to merge a supershape with a cylinder.
Looking at the geometry merge example patch, I've replaced the sphere with a supershape and now it doesn't draw to the canvas.

https://cables.gl/p/ImtFQW

If you add the unidexgeometry op (thanks radsnake) I noticed you still get some weird results when you chance some values in the supershape, reset and redraw it. Not sure it's behaving quite as expected.