Fix ZeroDivisionError

I originally had the division backwards (see b25c3854), so I was
checking the wrong part for a zero.  Oops!
Optionally analyze all of a user's repos

Handy!
Skip repos without issues

Otherwise we get an error!

This seems to be mostly forks, which makes sense.
Tweak progress meter for multiple repos.

This still isn't quite right (it's not backspacing enough), but I don't
want to debug it right now.