Saintflint Extruder Remix NEMA17 edition

Remix of the remixed Saintflint Extruder by sonnylowe:
http://www.thingiverse.com/thing:1265898

Original Saintflint design by mmemetea http://www.thingiverse.com/thing:987520

Easy to remove parts to service the extruder when needed.

I used the following parts:

- a standard MK8 drive gear (ID 5mm, OD 8mm)
- 624 bearings
- M4 nuts on the Bowden tubes to lock them in place.
- the spring I used comes from some clothing pegs:
http://www.aliexpress.com/item/1-SET-Home-quilt-clip-cloth