Fix a few typos in the tutorial, and integrate `tut` in the build process

Created by: romac

I tried to follow the tutorial by pasting the code snippets into a sbt console and found what appear to be a few typos along the way.

With this changes, the code compiles but this line

solver.assertCnstr(Not(prop))

fails with the following error: https://gist.github.com/romac/60bbc628fad06d1266c8a681f9b80043