Lm8uu, dual fan mount x carriage for prusa

With PLA as my plastic of choice, I found that objects with short layer times benefitted greatly from a fan directly at the extruder. Greg Frost's Lm8uu X Carriage with Fan Mount fulfilled this requirement for most parts. However when printing thin layers with short layer times I found the side opposite the fan could still come out messy. To remedy this I added a fan to the other side.