Speeduino v0.3 enclosure

First take on an enclosure for a Speeduino (http://speeduino.com) v0.3.x board.

Hardware required is 4 M3x50 cap screws and matching nuts.

7th December 2016 - Updated with better alignment and a version of the bottom that includes mounting feet.

4th March 2018 - Minor revision to fix small alignment issues with the feet. Thicker walls and slightly smaller MAP hole.