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
Bitmaps are now identified by an enum class instead of by pointers.
Bitmap loading and caching is now handled by a class in common, and
we no longer compile most bitmaps into the binary, so there is no
longer a bitmaps static library.
Instead, bitmaps are archived to a .tar.gz file which is installed
in ${KICAD_DATA}/resources/images.tar.gz
The source PNGs are checked in to Git as the original CPP files were,
so that people can build without the required dependencies to convert
SVGs to PNGs.
Initial support is also added for dark theme icons, although this
is not yet exposed in the GUI.
Stubs are present for multi-resolution image resources, but this is
not fully-baked yet and could use some refinement.
ADDED a new pin electrical type "free" for internally unconnected pins.
CHANGED the "unconnected" pin electrical type is now represented by
"no_connect" in files and netlists. (The legacy syntax is also accepted
in files.)
Scope: NETLIST_ITEM, CONNECTION_TYPE, ELECTRICAL_PINTYPE,
NET_CONNECTION, NETLIST_ITEM, GRAPHIC_PINSHAPE
Note, the pin type enum had PT_ added to the front to prevent
shadowing of the INPUT symbol on msys2 (see discussion at
c17c9960d8)
