HICTOP Circuit Board Cover Box

This is a reshaping of Nvalencia's elegant design from http://www.thingiverse.com/thing:1621685

Nvalencia's box was very attractive, but it was too wide to accommodate the position of the Z-axis stop on the pillar according to the assembly instructions from HICTOP. I wrote a few small modules in OpenSCAD to crop and trim an existing stl design, and used this to reshape Nvalencia's design to be a tight horizontal fit around the circuit board. While I was doing this I also fixed the thin-back