Prusa i3 Mk2 x-end stepper motor strain relief

This is a quick strain relief part for the x-carriage stepper motor on a Prusa i3 Mk2. Even though the x-carriage doesn't move very much in the z-direction in most prints, I didn't like the fact that there wasn't anything preventing the back-and-forth strain on the wires connecting directly into the x-carriage stepper motor. With two zip ties this can provide much better strain relief, moving the motion of the wires back into the cable wrap, rather than at the wiring harness connection of the mo