The coveralls link is broken; it's not just the case of "Slycot" in the URL, since both https://coveralls.io/r/python-control/slycot (the current URL in README.md) and https://coveralls.io/r/python-control/Slycot give 404s.

I don't know much about coveralls; is python-control/Slycot registered properly? Are we missing a step in the Travis CI build?

We could just remove this badge and URL.