Blockbot V3.1

STLs are up as build plates (2x).

Improvements from previous versions:
1. Improved printability. Should be able to print all parts without supports
2. Added and improved clearances.
3. Thickened up some of the thinner sections.
4. Pins are compatible with tbuser's Toy Robot Toolkit.
5. Blockbot now has a backpack/pen holder/rocket launcher tube/use your imagination thing on his back.
6. (V3 to V3.1) Pins printed horizontally for strength.

Big thanks to Lochemage for various design input.