A8 extruder feed observation port (OBSOLETE)

NOTE: This design is obsolete and has been superseded by http://www.thingiverse.com/thing:7164398

This mod allows one to offset the stock hot end cooling fan from its default position, replacing it with a round observation port that allows one to see straight into the extruder's feed mechanism whilst maintaining the flow of cooling air through the original heat sink.

The purpose of this is to aid real-time visual diagnosis of any mechanical faults during operation - for example, clogging, back