Reinforced 3 bolt Y axis motor mount for Prusa i3 mk3

Update 7/19/18 (finally!) - I finally got around to updating this post after a few members requested that I add in end stops to this motor mount so that is reflected in the new update (rev 3 file). I also added in a slot which is used to tighten up the set screw on the pulley. I have kept the original rev 2 file in case anyone wants that version instead of this new one.

Update 3/10/18 - I checked the motor mount in a 3D model of the prusa i3 mk3 with r2 components by jzkmath. The motor mount