Kossel Roller

Since I really like the simplictic solution here https://groups.google.com/forum/#!topic/deltabot/VM9439t1Ggc/discussion (yes, the site doesn't parse the URL properly), and I also have those Openbeam parts, I decided to try to create the kossel roller to make that design work. So far I've done what can be found here, but this is a work in progress. I decdided to put this here in the meantime, in case someone feels like improving or have anything else to improve this!

Main issue here is puttin