Parametric Prusa i3 combined J-Head/object cooling system Single-Double Fan

I modified the code in order to choose singular (left or right) or double fan. I also change some parameters to fit a 25mm fan and to increase hotend zone to fit my big 20W resistor.

It useful to use with AutoBedLevelling system: you can find the mounting plate at http://www.thingiverse.com/thing:397361

See instruction for more info.