Wemos D1 Mini OLED Mini Cube Case

[smily77](https://www.thingiverse.com/thing:857858) made one of the smallest best looking cases for Wemos D1 mini projects with an oLED. I made a few improvements to make it even more awesome:

* Display snaps into place (0.96" 128x64)
* Holes for a screw and cables to top-mount a temperature sensor (BME280)
* Mounting for two 6x6 buttons that are press-fit into the case
* Additional lip on the board tray to prevent it from coming loose

Printing:
* Print the case with the front down (no supports needed)
* Print the tray on its side with supports on build-plate only
* I've had good results with 0.2mm for PETG