Fine-grained progressbar using more Unicode block chars

Hey @Frozenball,

I saw that you had a bunch of different Unicode block characters in a list but you were only using one of them. I figured that you had the idea of using the others someday to show more fine-grained progress. That's what I did here.

This is nice when you're running a lot of slow tests as the percentage done might increment pretty slowly --without this, you won't see much happening on the PR; with this PR you can see the slow, steady progress.