- WorkflowRunnerTest: added a simple unit test for the WorkflowRunner class.
- WorkflowRunner: added parameter to and return result from the runWorkflow method, changed workflow input names for the concatenate workflow.
- DemonstrationWorkflowEngineTest: extended unit tests to test the "random lines twice" workflow as well.
- DemonstrationWorkflowEngine: reordered the statements of the runRandomLinesWorkflow method.