Bowden dual/quad extrusion extruder (single-nozzle single-drive) for MG995 SERVO

This remix will accept a MG995(R) Servo, This Servo is MUCH MUCH more cheaper than the ones used in original design (and have more torque also). Also I'm including changes to make a QUAD extrusion in Marlin 2.0.5.3 (tested and working !!!).

UPDATED (05/27/2020): Added a NEW idler MUCH STRONGER, this new idler uses two (2) M3 nuts for the spring screws, and one (1) nut for the bearing. This new design makes the construction more stronger to hold the screws in the idler. For the spring screw y