Filament Tube Guide

This is a variation on http://www.thingiverse.com/thing:8023 which can hold the PTFE tube (or tubes!) from http://www.thingiverse.com/thing:9604. On my ToM, the PTFE tubing sagged down after leaving the stacked guide to such an extent that it was deforming the plastic as it entered the extruder. This guide supports the tubes by the extruder and ensures that the openings remain perpendicular to the hole in the top. I made it so it could clip onto the side, since I hate having to unscrew those lit