Fixes rotating bitmaps with "rotate counterclockwise",
"rotate clockwise" and "move exactly" commands.
Only rotation by 0, 90, 180 and 270 degrees is supported
for bitmaps. Other values are rounded to the nearest 90
degree multiple.
There is a different bug that this commit doesn't address,
which is that BITMAP_BASE::Rotate() got its CW/CCW logic
reversed ("m_image->Rotate( false )" should rotate CW, but
does not).
Fixes https://gitlab.com/kicad/code/kicad/issues/14197
We report bitmaps as being 'on' a copper layer because they are
associated with it but they are not actually physical parts so should
not be included in the DRC checks
Additionally, Bitmaps effective shape starts are the top left corner
rather than the center (unclear why that was there in the first place)
Fixes https://gitlab.com/kicad/code/kicad/issues/14065
Also adds some debugging to try to catch dangling pointers.
Also adds a cache for group bounding boxes (which will be expensive
to calculate for large groups).
Fixes https://gitlab.com/kicad/code/kicad/issues/12875