Shutter Shades for small print bed

Remix of [Customizable Shutter Shades](https://www.thingiverse.com/thing:1603773) for print beds not larger than 120x120mm. This uses a pair of pin plate connectors over the nose bridge which is a little unsightly, but not too bad. On the plus side, you can mix and match different halves.

I made the hinges larger so that you can insert a bit of 1.75mm filament as a hinge pin. Make sure to insert from the top, because I made the bottom hole slightly smaller in order to grip the filament. Trim with flush cutters.

I also added a couple of different background patterns. They're all mildly annoying but I figure that's not going to be a problem.

Update 12/26: Added a frame model which is just a couple of mounting holes, to which you can attach a design that extends out of the glasses frame. These frames and a sample pattern are in files named "frame_left/right_mountable".

Update 1/4/19: Updated default STLs for 2020