add pen plotter image and end effector work

README.md

cad/detail/machine-layout-detail-joints-endeffectors.3dm

fab/3ax-example-fab/print/3dp-3dp-01.gcode

fab/3ax-example-fab/print/3dp-3dp-all-02.gcode

fab/3ax-example-fab/print/3dp-3dp-back.stl

fab/3ax-example-fab/print/3dp-3dp-mount.stl

fab/3ax-example-fab/print/3dp-3dp-mount.stp

fab/3ax-example-fab/print/3dp-pen-01.gcode

fab/3ax-example-fab/print/3dp-pen-back.stl

fab/3ax-example-fab/print/3dp-pen-mount.stl

fab/3ax-example-fab/print/3dp-spool-01.gcode

fab/3ax-example-fab/print/3dp-spool.stl

fab/3ax-example-fab/sheets/hdpe-eerun.stp

fab/gcode/ee-/01-ways-1-8-01.sbp

fab/gcode/ee-/02-ways-cutout-1-8-01.sbp

fab/gcode/ee-/02-ways-cutout-1-8-02.sbp

fab/gcode/ee-/03-ways-chamfer-01.sbp

fab/gcode/ee-/03-ways-chamfer-02.sbp

fab/gcode/ee-/04-else-1-8-01.sbp

fab/gcode/ee-pinion/01-face-1-8-01.sbp