Suggestions for Typeaheads filtered based on selected values.

#169 Working for Persons, Editors.
Not yet working for topics.
Not sure why you are doing this?
I'd leave the responsibility of doing this to the model https://github.com/ox-it/talks.ox/blob/master/talks/events/models.py#L137 , if we were deciding to change the way we do slugs that would yield a lot of confusions IMHO...