[MERGE] Add Mutt as a supported email client (round 2)

[Keir Mierle]

> > I also wrote a brief tutorial [1] on how to use gmail with
> > mutt and bzr send; it uses the included functionality.
>
> It looks like gmail should also work with the "editor"
> configuration, assuming you've selected the right smtp
> server/username/password.  Have you tried that?

Yes. However, I am not going to store my gmail password in
plaintext; especially since I version some of the config in
.bazaar/, and I'd rather not have my plaintext password floating
around on all the machines I've branched my configs.

Nevertheless, this is a good point. I've updated the tutorial [1]
to contain instructions for plain gmail via SMTP if you're willing
to store your password or type it in every time.

> I'll grant that mutt is nicer than "editor", but they're
> superficially pretty similar as they both use your text editor.

They are definitely similar. However, mutt gets things like
attachment filenames correct, and allows for other nice stuff.
It's generally a better experience than "editor". While editor is
a functional lowest-common denominator, I'd rather push people
towards using something more functional like mutt; especially if
it's easy to configure.

Keir

[1] http://bazaar-vcs.org/BzrSendWithGmail