default port => primary port

In some private correspondence, Henry pointed out that the spec would
be clearer if we referred to the "primary input port" and "primary
output port" of a step instead of the "default" input or output port.

On reflection, I think he's right. I'm going to go ahead and make that
change if no one objects. (Well, I'm going to make it anyway, but I'll
unmake it if someone objects :-)

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | It is undesirable to believe a
http://nwalsh.com/            | proposition when there is no ground
                              | whatsoever for supposing it is
                              | true.--Bertrand Russell