with_never=true for JaneStreet

We decided this is what we want for match and function patterns.  I made the change and I think I updated the tests correctly; please let me know if the pull causes any trouble.

We're using ocp-indent 1.0.1 internally and it seems to be working well!  Thanks!

Oh, and there is a tweak to tuareg-indent, which I didn't actually test!  Sorry, I forgot about that until now.