Progress bar not shown correctly on Windows

[thcyron]

On Windows, the progress bar is only shown correctly when the prompt is slightly larger than the default size (in width). Otherwise the progress bar is printed multiple times.

[thcyron]

Also happens on macOS and is a known problem in the uiprogress library in narrow terminal windows. There is no fix.

We can either:

1. Try to fix it ourselves.
2. Look for another progress bar library which does not suffer from that problem.
3. Ditch the progress bar and simply print the percentage.

[patrickschaffrath]

Fixed with #218