Occasionally, some input polygons contained self-intersections that caused problems with Voronoi diagrams and consequently with the extraction of colored segments by function extract_colored_segments.
Also, occasionally input polygons contained several points very close together (distance between points is 1 or so). Such close points sometimes caused that the Voronoi diagram has self-intersecting edges around these vertices. This consequently leads to issues with the extraction of colored segments by function extract_colored_segments.
MMU segmentation no longer works directly on lslices, instead of it works on custom merged regions. So lslices in PrintObject are no longer overwritten because of MMU segmentation.
All regions are scaled by SCALED_EPSILON before merging and shrunk back by SCALED_EPSILON after merging. That fixed issues with multi-volume objects when very close regions weren't merged.
Also, small expolygons and holes are filtered out that fixed missing segmentation at the boundary of two volumes in the case of multi-volume objects.
Steps to repro:
1. Add 2 objects, add Settings for some of object -> Object Settings item is selected
2. In the 3D-scene select another object -> BUG: no changes in the ObjectList
1) Removed the already commented-out scaling / unscaling when doing
"safe offsetting"
2) Removed some of the "safe offsetting" at calls where it never was used.
3) Reworked Clipper & ClipperUtils to pass Polygons / ExPolygons / Surfaces
as input parameters without conversion to ClipperLib::Paths. This
should save a lot of memory allocation and copying.
4) Reworked conversions from ClipperLib::Paths & PolyTree to Polygons /
ExPolygons to use the move operator to avoid many unnecessary allocations.
5) Reworked some "union with safe ofsetting" to "offset_ex", which should
be cheaper.
Serialization and deserialization in TriangleSelector were extended to support up to 16 materials (3 unused states left for possible later extension). These changes also affect the encoding of data from custom supports and seams, but it is backward compatible with the previous encoding. And for custom supports and seams, it is produced exactly the same data encoding as before.
