Mini Kossel Extruder for 3mm filament

I was stuck using 3mm filament because my other printer uses it and I wanted to be able to share filament. But all the other 3mm extruders I could find would cause a lot of skipping and grinding on the filament. So I just took Johan's original design and tweaked a bunch of stuff to make it work smooth.

1) Increased filament path diameter for 3mm filament (plus some wiggle room)
2) Moved the bearing 1mm farther away from the filament path to decrease pressure.
3) Extended the push-to-conn