Recommendation is to avoid using the year nomenclature as this
information is already encoded in the git repo. Avoids needing to
repeatly update.
Also updates AUTHORS.txt from current repo with contributor names
in most of files, including wx.h is not necessary, when only 2 or 3 wx files must be included.
Moreover, on windows, including wx.h sometimes create compil warnings about
shadowed vars defined in some specific windows headers.
panel_board_stackup.cpp: material selection:
replace wxChoice by a better widget (wxTextCtrl+wxButton) to call the dielectric manager dialog
Move dielectric material class to a specific file
In .gbrjob file, one can specify the thickness and color of some layers.
Currently, there is no way to enter these parameters.
This commit prepare a better support of .gbrjob files.
