Tutorial example added and a few English tidbits fixed up

Hi, I saw your talk at Clojure/west and have been meaning to try this out.  I had a spot of trouble getting started so I thought I'd upgrade your docs to include a short(ish) example about how to get started if you don't want to swallow the whole `strokes` repository to do your experimentation.  I'm open to moving this around or doing this some other way, but I do think the project would be helpful if your docs could point to this or a similar simple example.  Thanks!   --John