Fixed a minor bug in BaseStepDefinitionConverter in which the FormValues
were being populated to a list, but never set back on the Property.
Therefore Form Properties, like lists/enums were not well formed, with
their corresponding values, in the resulting BPMN model.

Added unit test for the same.
Merge branch 'form-values' of https://github.com/ddefrance/Activiti into ddefrance-form-values
Removed warning in test
Merge branch 'ddefrance-form-values' - Pull request #300