Fix method __unicode__ of return unicode(string) on articles models.
Fix method __unicode__ of return unicode(string) on articles models.

jeanmask/opps,williamroot/opps,YACOWS/opps,YACOWS/opps,williamroot/opps,jeanmask/opps,opps/opps,jeanmask/opps,williamroot/opps,williamroot/opps,opps/opps,jeanmask/opps,YACOWS/opps,opps/opps,YACOWS/opps,opps/opps