This test program illustrates how the ACE datagram multicast feature
works.  To run the test simply do the following on multiple machines:

# Machine 1
% ./ntalker

# Machine 2
% ./ntalker

# Machine 3
% ./ntalker

Then, on one (or all) of the machines, type input into the keyboard.
This input will be multicast to all the machines using IP multicast
via the ACE_SOCK_Dgram_Mcast wrapper.

When you want to shut down the sender, just type ^D.
