Extend skirt to print start position.

[carlosjln]

Add an option that extends the skirt line up to the nearest or perpendicular point where the print would start.

Context

My purge line is at the front of the printer, outside of the plate actually. Therefore my "Skirt start point" is set at -90deg in order to shorten the distance between purging and skirt start position.

I have enabled "Avoid crossing walls", hence you see the blue travel line taking the path of the shape of the object, that makes it have a retraction but it would actually benefit if the skirt would extend up to the perpendicular point where the object extrusion would start (you can see it on the top of the object because seam was set to rear).

Anyone has some thoughts about it?