1) Removed virtual methods. There was not really need for them.
2) Some of the virtual methods were using conversion to Lines, which
was unnecessary and expensive.
3) Removed some nearest element search methods from Point.
That allows computed better values in cases when the extrusion width of the first layer or for the infill differs from the extrusion width for perimeters.
Parameters min_feature_size and wall_transition_length now can be set in percentages, and then they will be calculated based on nozzle size. Old profiles with default values are forced to replace old default values with new default values in percentages.
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.
Relies to:
Concentric Fill Start Point - New Feature Request #4948
Feature Request: Archimedean Chords - Option to define direction of travel (Inside-Out or Outside-In) #5214
Fixed some issues in internal anchors of the Adaptive Cubic infill.
The ugly and dangerous implicit casting operators in Line, MultiPoint,
Polyline and Polygon were made explicit.
