PIGRRL 2 Improved buttons for TPU

The buttons for the PIGRRL2 are designed to work with hard buttons and TPE. I didn't have TPE, and when I used my TPU filament and the rubber dome buttons, the buttons scraped up against the side of the case and were horrible to press.

I've added a "strap" system where you hot-glue straps of TPU filament to the case, to add flexibility in just the right way to make it not hit the sides of the case and feel decent on the rubber dome buttons.

Glue at the end of the straight straps, look at first picture for other shapes.