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
The basic problem is that the DRC engine does length testing and skew
testing by collecting all the diff pair constituent parts and pairing them
itself. Since each part is collected on its own, we need to ignore the
'B' unit when evaluating any conditional expressions. However, doing this
in general means that when evaluating "OwnClearance()" we also ignore the
'B' unit and return the diff pair CLEARANCE_CONSTRAINT when we shouldn't.
This implements a more discerning test which know what the current requested
constraint is when evaluating expressions.
See also https://forum.kicad.info/t/solved-custom-differencing-rule-not-working-drc/34034/6
Fixes https://gitlab.com/kicad/code/kicad/issues/11314
