Hot-end fan mount with dual air flow

With the new Slic3r "Cooling" option, using a fan in the hot-end to cool the layers faster is a great improvement in the print quality and speed.

This part was designed to make it possible to cool down the hot-end heatsink and at the same time blow some air on the printed part, without dissipating heat from the hot-end itself.

I was very inspired by thing http://www.thingiverse.com/thing:16266 but also wanted to have airflow over the printed part.