Department of Computer Science, Radboud University Nijmegen, Nijmegen, The Netherlands. tvanlaarhoven@cs.ru.nl|Department of Computer Science, Radboud University Nijmegen, Nijmegen, The Netherlands. tvanlaarhoven@cs.ru.nl|Department of Computer Science, Radboud University Nijmegen, Nijmegen, The Netherlands. tvanlaarhoven@cs.ru.nl