Compact Compass

I got the idea for this project from John Heisz's recent video on his YouTube channel. You can find a link to the original and his updated version here:

https://ibuildit.ca/tips/making-a-compact-compass/

He also shows the tool in action. I thought it was a pretty clever design, so I decided to try making a 3D model suitable for printing. It probably would have been quicker to make one of these out of wood or metal than to write the OpenSCAD script and several test prints before I was happy with the result.

Mine is basically his design except I set the dimension so the max radius is 10 cm and added added a scale with markings from 1 to 10 cm. It also has en extra nub for the center pin. I'm not sure this is actually needed; John's seem to do just fine without it.

I've uploaded the script in case you'd like to play with the sizes and shapes. The placement of the markers is in the the module on line 47:

```
module markers(Rarm) {
linear_extrude(Th) {