This is a zero-dimensional object that can be used for snapping
and documentation of useful, but non-physical features on a
board or footprint. They do not correspond to any physical
output in exports or plots.
Points do have a "size", but this is a graphical property only
and determines how large they are drawn on the board.
They also have a layer, which allows them to be selected and
made visible according to layer filters.
Fixes: https://gitlab.com/kicad/code/kicad/-/issues/4691
This also removes the GROUP/UNGROUP-specific undo actions.
This also fixes a bunch of undo bugs when duplicating
group members, creating pins, etc.
This also fixes some undo bugs when dividing wires etc.
This also fixes some bugs with new sch items not
being created within an entered group.
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
There was a gentle mish-mash of booleans, some with
true being left/right and some up/down, and some functions that
can flip in both axes (which is never actually done, and doesn't
really make geometric sense).
Replace all this with the FLIP_DIRECTION enum class, which makes
the intention completely unambiguous.
This also then allows a small scattering of simplifications,
because everything takes the same type and you don't have to
fiddle booleans to fit.
