SimpleBot Pi design modifications for LCA:
* Removed some unused base plate holes for faster cutting.
* Shrink front bumper to clear Pi front plate (with 10mm spacers)
* Tweak centre of gravity backwards slightly to discourage tipping over forwards
Rename plates-sbpi to 'SimpleBot Pi parts'
Remove hidden 'Arduino' shape from SimpleBot Pi design
SimpleBot Pi - Add SVGs for panels (300mmx270mm, easy to cut from a larger 900x600 panel.)

There's a "2up" panel with the base/bumper panels for two bots, and wheels for one bot.
Then the "3up" wheels panel has wheels for three bots.