Unit test for https://github.com/Activiti/Activiti/pull/453
Merge branch 'master' of https://github.com/Activiti/Activiti

# By karnahla
# Via Joram Barrez (1) and karnahla (1)
* 'master' of https://github.com/Activiti/Activiti:
  set MultiInstanceActivityBehavior when executing service tasks (inheriting AbstractBpmnActivityBehavior) as delegate expression to avoid infinite loops