Added a block for stability

Great model, found the tolerances just a bit too tight for the gopro standard screw and nut. This might be down to my printer settings though.
I like to component approach, I could use the STL in OpenSCAD just fine. Prints fine, but is incompatible with my Hero 3+ case. The distance between the discs is too small, the fit is too tight. (edited)
Brilliant idea, I attached the box in a slicer and have everything I needed. Thank you. (edited)
