Support drawing with dithering on
monochrome palette mode.
JIRA issue: CORE-15990
- Enhance drawing routines for
dithering in drawing.cpp.
- Add VirtualBrush class to the
tools model in order to virtualize
the drawing colors.
- Move PaletteModel::CreateDitherBrush
to drawing.cpp ::CreateDitherBrush.
Co-authored-by: Hermès BÉLUSCA - MAÏTO <[email protected]>