* 1. Remove all global include_directories.
* 2. Move 3d party dependencies from src to budled deps if possible.
* Unify and enforce one way of including headers:
e.g. #include "libslic3r/GCode.hpp" vs #include "GCode.hpp"
(always use the "libslic3r/GCode.hpp" option).
* Make all dependencies (also header only) a cmake target.
WIP GCode/SmoothPath.cpp,hpp cache for interpolating extrusion path with arches.
Removed Perl test t/geometry.t, replaced with C++ tests.
Refactored ExtrusionEntity and derived classes to hold extrusion attributes in new ExtrusionFlow/ExtrusionAttributes classes.
Reworked path ordering in G-code export to never copy polylines, but to work with a new "flipped" attribute.
Reworked G-code export to interpolate extrusion paths with smooth paths and to extrude those smooth paths.
New parameters: arc_fitting, arc_fitting_tolerance
Renamed GCode class to GCodeGenerator
Moved GCodeWriter.cpp/hpp to GCode/
Moved Wipe from from GCode.cpp,hpp to GCode/Wipe.cpp,hpp
Moved WipeTowerIntegration from GCode.cpp,hpp to GCode/WipeTowerIntegration.cpp,hpp
New variant of douglas_peucker() to simplify range of iterators in place.
Refactored wipe in general and wipe on perimeters / hiding seams.
WIP: Convert estimate_speed_from_extrusion_quality() and its application to smooth paths.
WIP: Cooling buffer to process G2G3, disable arc fitting for filters that cannot process it.
Center esimtated curling - transfering data by nearest line caused CCW or CW shift, based on which point of the current line was used. By switching the points on layer basis, this problem disapeared
Dynamic overhang speed could sometimes wrongly apply volumtric limits
Also, setting speed to zero will now cause the algorithm to use base external perim speed.
Should fix the following issues: #9594, #9485, #9563, #9588, #9610
Also fixed a problem with zero speed when dynamic speed was percentage based and speeds were set to 0 (auto)
