Fidget D20 - Minor Updates

Recommended printing orientation for the icosahedron is to lay it flat on one face and use manual support painting on any large highlighted surfaces.  This avoids getting support material into the tiny holes.  Users of Bambu Studio can load the included 3mf file.

Print the numbered tiles face down on a textured PEI sheet.  Reducing elephant foot compensation to 0 and slowing down the first layer (to something like 25mm/sec) should help get a great first layer.

I rewrote the numbers/tiles in OpenSCAD, so the scad script now generates the entire model.  This allowed me to correct the placement of the center attachment point (it was off by about 1mm), as well as make the numbers flush for easier multimaterial printing.  Included is 3 types of STLs, depending on how many colors you want.  The generated STLs also have the tiles condensed to the center of the build area, so minimal changes are needed after importing into the slicer.

Lastly, a few tolerance adjustments were made to the icosahedron- the radius of each keyswitch center hole was enlarged and the hole deepened.