8-Bit Folding Cube for PLA

I could not get a PLA print of [Emmett's folding cube](http://www.thingiverse.com/thing:135836) to snap together without damaging the hinges, so I re-designed them. The hinge pins are rounded rather than conical, and there is a slit in the hinge to provide a bit more give when the pieces are snap-fitted together. While I was at it I decided to change the outward appearance to an 8-bit pattern to make it stand out from Emmett's original - which I think is awesome by the way !