* Prepared ConfigDefs for placeholders used in EditGCodeDialog.
* Removed unused code and files
* DEBUG mode only: Added check of placeholder's existence in custom_gcode_specific_placeholders and custom_gcode_specific_config_def during the custom G-code parsing.
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.
Added support_tree_branch_distance parameter to UI
Fixed error in calculation of placeable areas, which made some trees to cut through an object.
Locked the tree tips against smoothing of their centerline path.
Reduced density of tips with zero interface layers (see continuous_tips).
Reduced default support_tree_top_rate to 15%
Refactored placement of interfaces for readability.
Improved bridge over sparse infill logic - now does not bridge the whole area but only neede part
Filtered out tiny regions of ensuring created after bridge_over_sparse infill expanded the regions
Separate Alerts into new print object step so that not warnings are thrown for autopaint.
finally fix -1 access int SupportSpotGenerator bridge detection
- remove the infinite skirt
- added 'idle_temperature' in Filament Settings as an optional parameter
- the logic is changed: if idle_temp is present, it is used,
otherwise it uses the old delta value from Print Settings
- TODO: the optional parameter is not well supported in UI
