* Fix automatic overhang threshold
We should be supporting perimeters that are overhung further than half a
perimeter out, rather than two times the perimeter width.
Fixes: #2068
* Made the overhang detection configurable, up to 200 (the original value, which is still the default)
* Set default to 60% as per https://github.com/alexrj/Slic3r/wiki/Support:-Requirements
Removed some less useful enumerations (0-30%)
* Folded in auto_threshold into support threshold as a % value
* Make mouse-wheel in 2D toolpath zoom in the same direction as it does in 3D and 3D-preview
* Add a GUI preference setting for whether to invert the direction that
mouse-wheel scrolling will zoom in the 2D and 3D panels.
* Add weight/cost output to gcode. On the way to #647
* added total cost/weight to Extruder statistics, mocked up addendum to status bar change.
* Added second information box that populates after exporting gcode for sliced statistics.
* Changed filament density to use g/cm^3. Extended tooltip to indicate calculation methods.
* Hide sliced info box when gcode export hasn't been done.
* Remove if invalidated and we have background processing or the configuration changes.
* Called layout after every Hide/Show call to ensure that it is placed correctly on different platforms.
Changed output units to cm/cm^3
Conflicts:
lib/Slic3r/GUI/Plater.pm
The Clipper library has difficulties processing overlapping polygons.
Namely, the function Clipper::JoinCommonEdges() has potentially a terrible time complexity if the output
of the operation is of the PolyTree type.
This function implmenets a following workaround:
1) Peform the Clipper operation with the output to Paths. This method handles overlaps in a reasonable time.
2) Run Clipper Union once again to extract the PolyTree from the result of 1).
Conflicts:
xs/src/libslic3r/ClipperUtils.cpp
