Ender 3 Filament Guide easy install

Updated 6-July-2018 **

This remix accomplishes 4 objectives:

1. Allow the guide to be added without removing filament, simplifying installation
2. Only attach with a single screw to simplify installation
3. Kove the guide further away from the extruder to increase the angle of support, making it easier to pull on a spool that was poorly wound
4. Lower the guide itself so that the filament doesn't erode the extruder lever. Even plain old PLA is abrasive and will carve away the soft plastic used in the Ender-3's extruder lever. By lowering the guide, we can wear the cheap part (the filament guide) instead of the extruder lever.

In order to solve #1 a gap had to be added to the guide which then necessitated the additional support structure, tying the guide to the shield, which also makes support removal easier. A plate stiffener was added to account for the increase in distance from the extruder and the guide only being secured by a single screw.

06-July Update:

The guide was lowered by 1mm, widened by 2mm to make it more sturdy, and the filament guide support 'tower' was also raised by 2mm for additional strength.

In order to make the support easy to remove, use these settings in Cura :
Generate support: everywhere
**Support overhang angle:**80 (this will limit the support to just the left side of the filament guide)
Support Density: 15%
Support Z Distance: 0.1

Please note: if you print this in PLA, you should consider this a wear part in that the filament will eventually wear a channel in the guide and will need to be printed over time. This is true of all the filament guides where filament rubs directly against the guide (vs. using a roller).