This new implementation should resolve several types of artifacts with multi-material segmentation.
It should also increase the precision of projection, so sliced models should be much closer to how they were painted.
Also, the slicing of painted models should be faster than before.
Previously, colored polygons were stored so that each polygon had a color assigned to it, which made it difficult to perform operations like union or so on all polygons of the same color. Now polygons are stored grouped by their assigned color/extruder.
