Fix in MMFlowView+NSDraggingSource
Fix in MMFlowView+NSDraggingSource

- changed bitwise test for delete drag operation to explicit test for NSDragOperationDelete

alvinvarghese/MMFlowView,mmllr/MMFlowView,alvinvarghese/MMFlowView,mmllr/MMFlowView,alvinvarghese/MMFlowView,alvinvarghese/MMFlowView,mmllr/MMFlowView,alvinvarghese/MMFlowView