Top Mounted Spool Holder for Mini Kossel

This is a top mounted spoold holder.

A Smaller, somewhat sturdier version based off of http://www.thingiverse.com/thing:300553.
Can be easily printed on a round Mini Kossel bed.

Designed for use with 15x15 Open Beam Frame extrusions.

Also, corrected the symmetry so you can print two, without having to mirror the second one.