Prusa X Carriage with Slim LM8UU Holder - Modified to Better fit my MendelMax

I made a few modifications to simonkuehling's x carriage so that it would fit on my MendelMax better. These modifications include: shifting the belt clamps over so the belts are in a straight line with the pulley and moving the belt clamps farther apart so that the belt can be tensioned more easily. I also used the beefier (3mm thick) version of jonaskuehling's LM8UU clamps, and added a tab with holes in it to mount a printed opto-flag.

I've tried to keep it as parametric as possible. Ther