Arduino Uno Base

**[WIP]**

Base for holding Arduino Uno. Working on the rest of the case...

+ >180716: uno_case_lid.stl - lid to cover most of the adafruit motor shield, while leaving access to M3 & M4 and providing passive ventilation.
+ >180716: uno_case_highWall.stl - walls now reach to the same height as add-on boards such as the adafruit motor shield.
+ >170716: uno_case.stl - Original object for holding an arduino uno