Extruder test

The temp-control electronics, together with a stepper motor controller, have been packaged into a box, and I modified the EMC2 config to include an A-axis that controls the extruder stepper motor. The extruder seems to work, but the big cog-wheel that feeds the ABS plastic rod could be improved. It now slips a little too easily, especially when the corrugated area which pushes against the plastic rod fills up with small bits of plastic. Next up is mounting this on an XYZ-table and trying to 3D print something!