MM3 Fan Duct for dual extruder

I found maddavo's fan duct to not function with the way I had my hot ends mounted. I made the following changes to adjust this part for my use:

1. Widened the gap for the hot ends, to allow for hot ends with silicone covers.
2. Made the portion of the blower between the hot end and carriage much thinner, so as to fit comfortably.
3. Adjusted the mounting holes so that the fan could be mounted either closer, or further from the build platform.
4. Reduced the lip of the fan mount, so that th