Extruder Cooling for the Simple XL Upgrade Kit

This is a remix of the Extruder Cooling from Thing:187380. The original thing doesn't fit the Simple when the XL Upgrade Kit is installed.

For some reason MeshLab didn't swallow my partial scaling of the original thing so I made my own mesh using the original as a template as it is a proven design.

This extruder cooling will only fit with a 40x40 fan no deeper than 10mm. According to the information on the page of the original thing It should work on all Simple ordered earlier than October 2013.