Added build support for the new SSEM simulator and fixed minor compiler suggested cleanups
More compiler suggested cleanups
Use generic message routine for sim_accept_conn and sim_read_sock and don't emit a message if a read fails due to ECONNRESET (this is expected).
Add line number to line specific debug message output.
Change 8-bit characters to printable form.
Added per line Modem Control capabilities to TMXR
Added help info to asynchronous timer device
Added sim_getnames_sock to get a printable form of the endpoints of a socket
Added stability to virtual null modem connections by consuming all incoming per line connections until a good one (or none) is found.

Extended debugging to describe the socket endpoints when connections are established.
Extended XMT and RCV debugging to include the line number in debug messages.