#15 taskbar progress bar

[MBit]

On some platforms, notably Windows 7 and later, applications can display a progress bar on the taskbar button. The Cinnamon desktop can also do this through libxapps. Big question mark for other environments.
Ddrescueview could display the rescue progress there. Can be useful if many rescue ops are monitored in parallel. The overall rescue status would still be visible in the taskbar even when the windows are minimized.
Taskbutton flashing, a related feature, could be triggered when the rescue is finished.
The implementation would be completely platform dependent, Lazarus does not offer an abstraction.