- Add DoCreate methods to CFullscreenWindow, CMiniatureWindow, and CMainWindow classes.
- Do encapsulation around mainWindow and _tWinMain.
- Add GetOpenFileName, GetSaveFileName, and ChooseColor helper methods to CMainWindow class.
- Move some code in WinMain into CMainWindow::OnCreate.
- Delay creation of CFullscreenWindow and CMiniatureWindow.
- Extend ATL CImage class as CImageDx in newly-created atlimagedx.h of mspaint.
CORE-18867
