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
C++20 added new reverse and rewritten candidates. This can confuse the compiler because it'll test both A==B and B==A for overloads.
Because we were defining parent class equality overloads, A==B and B==A was considered ambigious due to both being compatible in casting.
So we needed to add explicit child class equality operator overloads
