K8200 electronics cover fan inlet duct

A duct to quieten the fan inlet noise on all those K8200 electronics covers. Works on fans with 32mm bolt centres.

openSCAD parameteric as usual

Not to be confused with the extrude cooling ducts. Works with these:
http://www.thingiverse.com/thing:168769
http://www.thingiverse.com/thing:162735