o basic transformation into polygon extruding.
o re-add template based screw function.
o read arbitrary polygon from file.
o Make 'make clean' remove objects.
o rename 'radius' to 'initial_size' to better reflect its use.
o calculate radius from polygon for offset reasons.
o more robust reading of polygon.
o move polygon offset in separate file.
o do offset the CGAL way.
o add pump parameter.