HiDPI support

[rodlie]

Required for HiDPI support:

• [x] QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
• [x] #22
  • [x] Position
  • [x] Pan
  • [x] Resize
  • [x] Scale
  • [x] State
• [x] Fix color widget (identical issue as in #22)

[rodlie]

fixed in wip