Spider Battery box

Early draft.

[Landvien](https://www.thingiverse.com/Ladvien/about) and I have been building the [spider bot by regishsu](https://www.thingiverse.com/thing:2204279), but wanted to put in a battery box that was easy to remove for recharging, and use a Raspberry Pi Zero W for the brain plus a servo controller.

Modifying the [Parametric AA battery box by jetty](https://www.thingiverse.com/thing:1190819) (thanks for pushing me from a GUI to SCAD!) I switched the mounting lugs out for hinge pins.