ToyREP Stepper Motor Cooling

This upgrade of [ToyREP](http://www.thingiverse.com/thing:945156) will allow you to attach 40x40x10mm fans close to X, Y and E motor for better cooling and reliability. Fans may even let you use a bit higher print speeds. These models are prepared for 28BYJ-48 with four mounting holes but are also backward compatible with more common motors with two holes only.

Models should work, although I did not print them my self yet. My fans are already glued to similar positions, so I don't need th