The better X line tension-er for Printrbot Simple alpha release.

Alpha Release: I wasn't satisfied with the tensioners I found online, so I designed this one. It will not limit the full range of X axis travel. It mounts on the side of the print bed mounting plate. It can actually mount to either left or right side. From what I have read, and my experience with axis slippidge, you need to tighten that 200 lb line almost daily before you attempt to print. That gets cumbersome with the original factory design. This version simply uses a 3mm screw, 25mm long and