#10 Change DNX port numbers to IANA-assigned port (3998)

[John Calcote]

DNX has been assigned an official IANA-assigned port number, 3998 for both UDP and TCP transports. Change DNX client server communication port number from the random one we chose (12480/81) to the official IANA assigned port 3998.

In addition, reorganize communications such that we use only a single assigned port value, rather than two.