ietf-nntp Common NNTP extensions document updated

[Stan Barber]

A new release of this document has been submitted to Internet Drafts.
I have requested that the name "draft-ietf-nntpext-imp-00.txt" be used, but
they may want to call it draft-ietf-nntpext-imp-09.txt since it is the 10th
version of the document.

The changes involve some clarification of the streaming extension and a few
other small changes.

As soon as I know the real name, I will post it here.