Cones for Paper Towel Roll Holder

The current cones are pretty worn out.

Simple, customizable design in two versions:
- v1 Straight edges
- v2 Rounded edges

For the STL rendering I experimented with the "print fineness" setting FF.
For instance, for a circle/cylinder the $fn is set by FF*D.
Normally I set FF to 16, which is PI over 0.2 (which is my current print layer thickness).
However, a FF of 16 leeds to very long STL rendering time.
But as the old saying goes: Render once, print forever ;-)