FroZen Extruder - alternative Makibox extruder v1.1

The Makibox "Zen" extruder is remarkable for its simplicity and low-profile design. However, in its first shipping version, it has some issues, notable that the idler tension is not adjustable and the idler wheel spokes often break, leaving one with an extruder that doesn't work reliably. This my design for a replacement extruder that addresses those issues.

Primary design criteria were:

1) Must fit in the existing Makibox extruder location.
2) Must utilize the Makibox standard stepper a