X-Carve 2015 gantry wire management

WIP. Parts have gone through a few revisions now and tested with wires, but changes are still happening.

Update April 10, 2018: Haven't done any extensive testing, but everything seems to work just fine. I do need to strengthen the molex bracketry a bit though. I had a couple of them snap on me while I was pushing in the fittings. Still, not bad!
https://youtu.be/Arqq7JOhiF0

I'm modifying my Shapeoko 2 with a first run X-Carve upgrade kit from 2015. So, it's missing holes here and there