Also removes the return value from the BITMAP_STORE's themeChanged
method as it will provide the wrong answer for the second frame it's
called on.
Also hooked up ACTION_TOOLBAR, the app launcher, and the project tree
to the wx event for system color changes so they change on the fly.
Fixes https://gitlab.com/kicad/code/kicad/issues/6026
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.
Marek Roszko
Seth Hillbrand
Jeff Young
Jon Evans