NNTP working group catchup

I'm now caught up on the NNTP working group traffic again, and have posted some general information and some questions about how we should handle LIST OVERVIEW.FMT going forward to news.software.nntp. Hopefully we'll get enough information to decide that question soon. I'm still in favor of not standardizing it, but maybe someone will come forward who actually uses it.

I think the only major unresolved questions left are whether to keep the special language for using <0> to handle messages without a message ID, the LIST OVERVIEW.FMT thing, and how to handle 480 and 483 (for groups that need a privacy layer) in the basic specification. We should be able to make our April target.