Prusa i3 (China) cooling system

This cooling system is based on ideas drawn on this site.
This cooling system is adapted to the Chinese PrusA i3 assembly.
This cooling system uses a standard fan 40 * 40 mm, and allows you to create two streams for blowing the extruder and the printable area of one fan. You can set the printable area illumination with LED ring diameter of 60 mm.