Report how many log messages are pending

[fhunleth]

Despite what I thought were hints to run RingLogger.next to see log messages, new users still aren't seeing them.

I was wondering if having a log message counter in the MOTD might help. It would say something like "23 unread log messages". This requires an extension to RingLogger to implement.

Perhaps there are other ideas. Before one of us implements, I wanted to discuss options here. Maybe there is something else simple. I do believe that people read the MOTD, though, which is why I'm creating the issue here.