Rounded cube (torus)

Rounded cube based on torus. Better shape but slower. Makes smoother fillets than created by hull of standard spheres.

This cube allows:
- __fillets__ in each __axis__
- __fillets__ of each __corner__ independently
- __chamfering__ in z axis for easier printing
- __centering__ in each axis independently
- __moving__ cube on the other side of the axis (center = 2)