Superformula vase

I'm writing new functions for [my library dotSCAD](https://github.com/JustinSDK/dotSCAD) and here is a demonstration about how to put them together.

Different shapes can be generated by choosing different values for the parameters of [Superformula](https://en.wikipedia.org/wiki/Superformula). The curve is generated by [Bézier curve](https://en.wikipedia.org/wiki/B%C3%A9zier_curve).

Even though I leave 11 parameters on the customizer, the vase can be generated by more parameters. If you want to control more details, download and modify `superformula_vase.scad`.