ACTION-348 some draft text re redirection + address bar

http://www.w3.org/2001/tag/2010/02/redirects-and-address-bar.txt

Written in the style of a blog post, and making use of
state-of-the-art theory (such as it is) of http semantics.

If this gets review and approval of some kind (especially from TimBL,
who has been the vocal campaigner on this question) I'll htmlify and
post it and be done with this action. Not sure what else to do.

Jonathan