FFCP 2016 filament feeder (improved)

This is a remix of [tim_sweden's filament feeder](https://www.thingiverse.com/thing:1701657) for the 2016 edition of the FlashForge Creator Pro. It offsets the filament guide tubes so the filament unwinds more uniformly from the spools.
This remix has a more hollow design to reduce the amount of material needed for printing it. It also has tapered holes for easier insertion of both the tubes and filament.

Another change is that the holes do not allow the tubes to go all the way through. Not only does this make it trivial to align the tubes, it also helps if you have nasty poorly wrapped filament spools that are tangled to such a degree that the extruders pull hard on the filament. If that happens, there is a downward pulling force on the tubes, and there would be an increased risk that the filament gets completely tangled if the tubes would be pulled below the feeder.

I recommend mounting the feeder in the topmost clamps, especially if you use filament filters like on the photo.