Prusa i3 Metal Frame Filament Guide Revisited

This is a second iteration of http://www.thingiverse.com/thing:114083 . The loops for the filament are larger and thinner. Depending on the feed angle of the filament, the first iteration was sometimes restricting the filament movement.

Furthermore, there are four files: two for a dual extruder and two for a single extruder printer. Each group has a 6.5 mm and a 7 mm grip width. Depending on the material, the 6.5 mm version is sometimes a bit too tight.