Extra perimeters if needed : overhangs

left	right
normal	with this option

85% overhang test

This Feature add to "Extra perimeters if needed" an other feature. It will add a perimeter as long as an infill surface is on an overhang area. Also, it changes the perimeter extrusion direction (clockwise / counter) every layer if an overhang is present, this to prevent a drop on one side.

note: "Extra perimeters if needed" did nothing before.