Add the process ID to the log statements
Set alarm and severity codes on PV's

Set the EPICS alarm and severity codes to NO_ALARM when outputting the
PV values.  (Also set INVALID_ALARM if we're asked for a PV we don't know
about, but I'm not sure that matters since we return 'None' for the
value in that case.)
Restart the live listener if it quits

Added code to restart the Mantid live listener algorithms if they exit
for some reason.  Also added code to catch and log exceptions if
something really bad happens down in the listener.  (Can't recover from
that, though.  It just logs the exception and exits.)