Yet Another Wanhao Duplicator Spool Holder

(Yet another) Replacement spindle for the filament spool holder on the Wanhao Duplicator i3 series printers...with:
- Larger diameter for smoother filament dispensing.
- Over 80 mm of useful shaft length to accommodate even uncommonly large spools.
- All overhangs comply with the 45° rule. (Print on end, with threads up)

For tall, skinny Makerbot spools, check out [driph's remix](http://www.thingiverse.com/thing:1999009).

While Fusion 360 automatically adds a bit of tolerance to threads, a lot of people have had trouble with getting the nut to fit. To that end, I've added a version of the nut with an additional 0.1mm of tolerance. Hopefully that should solve the problem.

*Note: This does not work with the stock nut. I wish I had designed it to do so, but it was the very first thing I designed in Fusion 360, and I wasn't prepared to try to match the thread sizes, sorry.*