HotEnd Mount for E3D v6 on Rostock with improved cooling.

I have noticed that the cooling from the original mount did not provide the level of cooling for the cold side that I liked. This was due to three things.
1. The shape of the cooling channel. The original had a straight through channel with an overall rectangular shape. This allowed air to flow unevenly through the heat exchanger.
2. The shape of the opening for the fan. The opening was, like the cooling channel, rectangular in shape. Since the fan itself, not the frame, is circular. This re