Proximity sensor mount remix for Wilson direct drive extruder.

Remix of [Proximity sensor mount for i3 Rework E3D Extruder v3](http://www.thingiverse.com/thing:763041) that can be mounted on the [Direct drive extruder for Wilson or Prusa i3 rework](http://www.thingiverse.com/thing:501755).

From the original proximity sensor I moved the nut countersinks and bolt holes out so that they would fit the width of the screws. I also added 5mm to the height of the sensor so that the mount would sit in the middle of the sensor. The original needed the nut to be w