Merge: Fix Opportunity behavior with unicode characters

Fix #1695. It is already deployed on http://xymus.net/opportunity/ (Take a look at http://xymus.net/opportunity/?meetup_id=B962ECD89E0AE40FF888569AE8D816B36F128E10)

Pull-Request: #1700
Reviewed-by: Jean Privat <jean@pryen.org>
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>