Finish sendto() support for UDP sockets. Should now be totally
compliant with the Version 3 line format, as described in libnetmon-format3.txt . Note that I have made a couple small changes to the output format: Write was renamed Send to be consistent, and I'm allowing Connected events for UDP sockets, in the case that the application actually does connect() the UDP socket. I'm not sure what we'd use this information for, but it seems useful and is easy to ignore. libnetmon is getting big enough that I should probably spend some time soon doing code hygiene.