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
if it is running under single_top.cpp or under a project manager.
*) Test Kiface().IsSingle() when adding menus, some operations are not permitted
when running under a project manager and the KIWAY_PLAYER is pegged to a
specific project.
*) Implemented KIWAY::KiFACE() so it loads *.kiface files. They still have to be
in the same directory as the main *.exe launcher, so this presents some difficulty
when the binaries are not yet installed but rather the *.kiface files are still
in their original build directories. For today, I simply copied _pcbnew.kiface
to build/kicad/.
*) Add a test case to kicad/mainframe.cpp just to get an early peek at loading
_pcbnew.kiface under the C++ project manager. Got that working for one
specific invocation just for proof of concept. Surprise, it works.
