Prusa i3 Compact Extraptor

___17 Aug 2013__ I decided to start from scratch and create a more concise compact extruder with better mounting, and which has the SCAD centered on the point where the gears pinch the filament, so it can be customized more easily. Check it out at http://www.thingiverse.com/thing:135368 for comparison._

I started with the Compact Extruder modified by http://www.thingiverse.com/misan for the 2engineers.com 50:1 Geared Stepper Motor (42BYG48HJ50). I then made the following additions:

* More tunable parameters
* An option to draw the assembled parts
* Minimized extruder option (extraptor_v2)
* Hinged Idler option
* Idler axle offset
* Adapter for the i3 "mini" x-carriage, inverted
* Hinged fan mount. Angle up for ABS, down for PLA.
* Fan duct attachment to concentrate air on the hot end
* Universal GT2 x-carriage, with 24 to 30mm holes, plus top "mini" hole

The included adapter is designed for the T-shaped "mini" x-carriage in the inverted position. (The bottom sc