Better fix for 11750. Instead of figeting with layer values, we sort
our map based on the layer numbers in the PCAD file. F_Cu is always
layer 1 and B_Cu is always layer 2.
Fixes https://gitlab.com/kicad/code/kicad/issues/11750
(cherry picked from commit ac0f95683f)
According to the PCAD specification, all tags are case insensitive.
Most exporters honor the defaults but there is always an outlier or two
Fixes https://gitlab.com/kicad/code/kicad/issues/11652
(cherry picked from commit 35b79c2ec9)