overriding ALL versions of an overloaded function.  These were addressed
     by filling in the rest of the API.  In some cases, a subclass was
     overriding and overloading a function (changing input parameter to a
     more specific type).  For these cases, we "hid" the original function
     in the private section of the subclass.  There was one internal API
     change.  SetInput/Output(i, vtkDataObject*) was changed to SetNthInput/Output(.)