Pandagrapher

Results 2 issues of Pandagrapher

This PR brings "real" Hi-DPI support for RawTherapee GUI. Except for image related custom widgets (ex: thumbnail, image area, ...), all the RT GUI has been migrated to handle Hi-DPI....

@Benitoite Fixes issue #7148 Fix for EditWidgets mode OM_65535 Fix for mode switching between OM_255 and OM_65535

scope: GUI