Even though KiCad8 can read older symbol files, this change is needed
to make future additions to the library easy to review.
KiCad8 introduced a new way of indenting. Even when changing just a
small text, that would result in a huge diff when saving the KiCad7 file
with KiCad8. Those diffs are hard to read making the life of the library
team difficult.
DRC is not yet smart enough to distinguish jumpered pads when they
touch, so we work around this for 5.1 by using graphical polygons on the
F.Cu layer.
In KiCad 4 there were no polygon pads which resulted in some overlapping
pad constructs. This is no longer required, as well as the old system
causes some nasty problems like duplication of pin numbers and
unconnected warnings. This PR solves the issue for the jumpers by
converting the pads to custom shaped pads as appropriate.
