Geeetech Prusa i3 Pro B Air Duct for Titan radial fan

Hello, this is a remix of PrintingGulliver's [GeeeTech i3 Pro B Air Duct](https://www.thingiverse.com/thing:2345045 "Title") (thank you very much!).

I wanted a PWM controlled radial(turbo) fan for my printer and I found out there are only a bunch of models on the internet, one of which is the TITAN TFD-B6015M12B.

Thus I modified PrintingGulliver's original design adding a larger intake capable to fit my fan: I also added a support to secure the fan to the mount (using a single bolt).