Raspberry Pi Zero Case - BETLOG version

- A quick modification to this case:
https://www.thingiverse.com/thing:1998032
- Removes the GPIO slot because my board has no pins.
- Altered standoff heights/radii for easier board insertion *and removal*, and added new standoffs to the lid to hold the board down.
- Added friction retainer slot/ridges to case/lid to make frequent removal of the lid easier and more secure.
- Extended case by 2mm at ribbon cable end, for better general clearance and to allow cable to be attached. I'll proba