Skelestruder for Prusa i3 MK2

This is a modification of the Skelestruder for Prusa i3 mk2 which I made because I have that printer and wanted to mount that extruder on it. STEP files for all models provided if you want to modify this further.

Changes:
1) I made the x carriage a bit slimmer (to make it the same width as the original mk2 carriage) and added the endstop lever.
2) I changed the position of the cable holder on the x carriage cover based on where the mk2.5 has it to make the cable clear the MK2's narrower fr