Removeable Spool Holder Arm and Bracket for Lulzbot Mini

This is a modification of the standard spool arm on the Lulzbot Mini. It replaces the hinge with a simple U Bracket, using the same mounting holes on the frame. The advantages are two-fold. First the hinged arm caused no end of trouble when moving the printer. It flops down at the worst possible times, and when in the folded position, it doesn't really sit inside the profile of the case, so it is easy to snag on things. But, most importantly, because the hinged mechanism crosses the plane o