Clip for E3D Integrated Bowden

The new E3D hotends (Lite6, V6) have an integrated bowden coupler. This works great, but if the black collet gets pushed down it can cause the PTFE liner to come free, which can lead to the hotend jamming or failing. This is a small clip that goes around the collet, preventing it from pushing down and releasing its grip on the PTFE tubing.

I was inspired by http://www.thingiverse.com/thing:977392, but seeing as that is for the external bowden coupler I designed this one for the newer internal couplers.