Case for pico_test_synth CircuitPython synthesizer

The pico_test_synth pcb was originally designed to be held up by four M2.5 standoffs and screws, but I wanted a simple little case that was easy to snap on and off.  This case has two tabs that will hold the qtpy_synth PCB well enough but allow you to pull it out without much effort.  If you want a more secure attachment, you can still use M2.5 screws and nuts.

You can also get the "OLED standoff brace" from “qtpy_synth case” to optionally print to help hold up the OLED display.