This adds the upper-case version of files names to the selection box for
filesystems that support case-sensitive file names.
Fixes: lp:1832853
* https://bugs.launchpad.net/kicad/+bug/1832853
* 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.