make logfiles easier to match to rooms

[plaza-in-a-heatwave]

To make responding to bugs a little bit faster, include info like the port in the logfile name

From previous discussions:

• Could maybe use system.out.println for error messages until args are parsed, then create a logfile with knowledge of args
• Could re-use the same logfile if we avoid timestamps in the filename (e.g. if 5 rooms, then create 5 logs, not 5, +5 each reboot)