Get multi-device drag to use ActionClass

EduNetworkBuilder/NetworkBuilder.cs

@@ -1579,6 +1579,11 @@ namespace EduNetworkBuilder
                 {
                     //We were dragging stuff.  All done now
                     MouseIsDown = false;
+                    foreach (NetworkDevice nd in ItemsSelected)
+                    {
+                        //Do an action move to the new location.
+                        NB.DoActionMoveDevice(nd.GetUniqueIdentifier, nd.myLocation());
+                    }
                     ItemsSelected.Clear(); //clear it so we stop moving these ones
                     UpdateLinks();
                     UpdateVisuals();