Prusa i3 groove mount with proximity sensor holder

I've made a groove mount designed for Prusa i3 Vanilla.
Target proximity sensor is LJ12A3-4-Z/BX.

I designed it with OpenSCAD and used [nutsnbolts library](https://github.com/JohK/nutsnbolts).
Proximity sensor fasteners are M3 bolts and nuts.

Feel free to edit my OpenSCAD code regarding the license.