A3 Feeder Improvement

This is based on the A6 Feeder Improvement by Athanasus. Using this assembly it is easier to thread the filament down through the mechanism to the hot end and there is more support for bendy soft filaments.

Many changes have been made to make it fit the Anet A3 and be more user friendly. I have now one assembly that is taken off once the two screws at the bottom are undone. I have redesigned and drawn from scratch the Filament Guide Plate and reduced in thickness the lever to account for the