Textured fidget cube

This is a slight modification to the [Customizable easy print fidget cube](http://www.thingiverse.com/thing:2119728) by Aahz, to add textured surfaces to the cube faces. One of the faces is the [Companion Cube](http://www.thingiverse.com/thing:915) by gianteye.

The bottom face has a tread pattern that tends to get wiped out when the first layer gets squashed during printing. The only way I have been able to recover this is by printing with a raft, which is a hassle to remove and makes the bottom face very rough. So when printing, expect the bottom to come out flat and featureless. I don't have a good solution for this.

I included blank_cube_single.stl to give a sense of how large the cube should be, if you choose to customize your own fidget toy. Just replace textured_cube_single.stl with your new cube model and run the OpenSCAD script.

6/28/24 - Updated SCAD script to fix some warnings.