Make the stat printing *pop* with colors and newlines

[faern]

I got this feedback from a colleague. That it was hard to read the stats because it was printed juuust after all the errors. Hard to see where the errors stopped and the summary started.

I fixed this by doing two things:

• Add a newline before the summary text, if any errors had been printed ahead of it
• If stdout supports colors, use them! Prints the stats in green when there are no errors and red if there are errors.

[gregoire-mullvad]

I tried this and it seems to break cargo run for me: it hangs just before printing the stats 🤔