Eventorbot Symmetrical Dual Extruder Mount

A mount for two Wade's Extruders for dual-headed usage on the Eventorbot.
Also included: an adapter for dual spool holders.

I took kkronyak's eventorbot extruder mount and mirrored it around the central screw point. This allowed me to mount a spool holder underneath each one to create a clean, self-contained dual-extruder printer.

Note: I have updated the Double Spool Adapter to rev 03. Rev 02 widened the part, and rev 03 moved the spool mounts 5 mm further from the frame. I found that some spools were interfering with the bed when I dropped the Z-axis far enough.