SP36 diffuser

### Why

Quick design for a diffuser for an SP36. Based on measurements from reddit's /r/flashlight, currently untested.

### Features

* Has a little ridge to stop the diffuser from sliding too far
* Top has an inward spike that (hopefully) distributes light in a donut-shape around the light when tailstanding
* Designed for 49.2mm fit - scale up or down if it doesn't fit right.

### Instructions

* Should be printable without supports when printed with the flat part on the bed.
* Use a .4mm nozzle (walls are 1.22mm thick)

### Open Source

As always the original design file is included, so feel free to improve it (or learn from it)!