MK8 -MK9 Support with autolevel 18mm

Based on Mk8 Extruder mount for Prusa i3 Rework by inornate - on http://www.thingiverse.com/thing:835475,

Thins is most hard, and the support has robust hole for inductive sensor:
* NEMA 17 stepper motor is a stepper motor with a 1.7 x 1.7 inch (43.2 x 43.2 mm) faceplate.
http://reprap.org/wiki/NEMA_17_Stepper_motor
* Inductive Sensor 18mm ( DC 6-36V NPN NC 5mm Inductive Proximity Sensor Detection Switch LJ18A3-5-Z/AX ) like
https://www.amazon.com/Inductive-Proximity-Sensor-Detection-L