*Fixes in the SVG import polygon postprocessing:
- don't drop subsequent polys when a non-filled primitive is imported 'in between'
- fix missing holes (also related to the interleaving of stroke and filled shapes, depending on the software that wrote the SVG file)
*GRAPHICS_IMPORTER_BUFFER: forgot to store the indices of the paths belonging to a compound shape
*pcbnew: GRAPHICS_IMPORTER can now recognize multi-path shapes (and postprocess polygons with holes into Kicad-compatible fractured polysets)
*SHAPE_POLY_SET: polysets can now be built from a bunch of arbitraily ordered oriented outlines.
Used by the SVG hole support
*SVG_IMPORT_PLUGIN: enable postprocessing of polygons with degeneracy and holes
*pcbnew: SVG importer support for even-odd fill rule
DXF blocks are virtual groups of items.
The insert entity is what actually places all the block contents at a given coordinate.
This should fix importing drawings from professional CAD tools like SolidWorks that will have a good bit of blocks.
* Do not compile dxf old files.
* import gfx, gal mode: make absolute placement working.
* Import gfx in legacy canvas: use it and make interactive placement working
* Take imported line width in account. Ensure DXF line thickness is OK.
* handling empty files in legacy mode.