fix and regenerate vignette
fix and regenerate vignette

newly strict tibble revealed that I was using `metadata(m)$journal` to
access `metadata(m)$journaltitle`.

Also, hide the progress report from `simplify_state` (invoked by
write_mallet_model).

agoldst/dfrtopics,agoldst/dfrtopics,agoldst/dfrtopics,agoldst/dfrtopics,agoldst/dfrtopics