WIP: [feature][Communication] Make GridView return a communication future object.
This MR provides suggestions how to enable a future object for non-blocking communication. If the grid implementation does not provided this then a dummy object is returned that will print a warning if the features are to be used.
gridView.communicate( ... )
will work in any case. However, code that now uses
auto future = gridView.communicate( ... )
will fail if there is not at least a dummy future returned. This MR fixes this issue in the interface class, in case the implementation still returns void.