Issue_54 put in boolean to check if mvdm handlers were already added to the QWorker so that it is only added once
Issue_54 put in boolean to check if mvdm handlers were already added to the QWorker so that it is only added once

vistadataproject/nodeVISTA,vistadataproject/nodeVISTA,vistadataproject/nodeVISTA,vistadataproject/nodeVISTA