Parametric Cube Fidget Spinner

Following on from my [Parametric Dodecahedron Fidget Solid](https://www.thingiverse.com/thing:6924662), I made another one that's a regular cube.

This is totally parametric -- edge/corner radius, bearing radius and depth, and overall cube size are customizable, so if you want a giant cube with sharp edges (drop the radius to 0.0001), you can do that. There's also an option to have (or remove) a central bore hole that goes deeper than the bearing hole depth to keep the back end of the bearing where you hold it freely rotatable. All the config options are clearly annotated in the OpenSCAD source with a bonus ascii-art dimensions illustration. If you're rendering your own, check out `Extending/Editing` below for an important note.

### Assembly

When you assemble, I strongly suggest finger-pressing in just the edges of the bearing into the hole to make sure it's even (if you have support cruft you might want to scrape out the bearing hole with a craft knife), then inverting it on a table