Arduino & Breadboard, square pins, solid back

I needed a robust Arduino+breadboard mount for the school.

Modified it to take the breadboard from the top, and to have a solid back (so the kids don't get to play with the double-sided tape already applied.

Also moved the Arduino mount down 3mm so that the USB port is not sticking out allowing for easier storage.

Screw the Arduino in with 4x M2 5mm screws.