+ removed // operator (perl >= v5.10.0)
- apparently the 'require' in DDC/Concordance.pm wasn't catching
- caused cpantesters failures for perl v5.8.x, e.g. http://www.cpantesters.org/cpan/report/2ad78a32-31ff-11e6-aa87-16280081755b
- also likely responsible for failed 4add1b26-3173-11e6-99be-4eefed1f9a26