Authentication Enhancements

[Matthew Metnetsky <met uberstats com>]

All,

I'm looking into adding Windows support for NTLM/Negotiate and was
hoping to receive some general guidance so that its done in a way that
honors your existing goals and design.

With that said, the current NTLM support built on-top of Samba tries to
grab the username from the environment, which doesn't seem as versatile
as it should be. I would like to start by having a way to send
user[/pass] down through the objects. However, the only way I see to go
about setting the "Authorization" header is either explicitly, or
through the "authenticate" signal. The former requires redundant code,
whereas the latter is reactionary.

I noticed the `soup_message_[get|set]_auth` functions which will set
"Authorization", but they're private. Is there a harm to making these
methods public or should "Authorization" be handled purely on
SoupSession? If so, how?

Any and all help is appreciated.

Thank you,

~ Matthew