ooznest OX - Belt Tensioner

I remixed this so it can be used with the Ooznest OX's Y Axis. The problem with the original design is that the bottom hole of the base is different vs the openbuild's OX (the hole on the Ooznest is covered by a the corner plate). I have extended the base and put a new hole in so that the plate is no longer covering it (the next hole in the extrusion). Huge props to the original designer as this is a much better solution for the belt tension then smashing the belts with a M5 screw.