There is a circular dependency between the GRAPHICS_IMPORTER object and
the GRAPHICS_IMPORT_PLUGIN object which makes sharing the settings in
the GRAPHICS_IMPORTER unwieldy. This fix is a ugly hack that resolves
the issue. The underlying issue will require some major refactoring.
Fixes lp:1821234
https://bugs.launchpad.net/kicad/+bug/1821234
* 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.