Add another folder to the gmail client map

This is really a horrible idea.  I need to figure out a way to
actually deal with this correctly.  I think I really need to rewrite a
whole bunch of this stuff, though...
Invert a strcmp() comparision

I really wish they hadn't done this.  I regularly forget about the
backwardsness of strcmp().
Work around a Krste bug

Some people start their messages with an extra blank line, which is
just entirely wrong.  This fixes the problem by stripping the extra
blank line.
Handle MIME message continuations

So I guess it turns out that MIME allows text to be continued with an
'=' at the end of a line.  This patch handles that problem.
Add a (simple) mailrc parser

This doesn't currently parse aliases, and it'll choke if messages
don't have names, but at least it's something!
Have "scan" output user names when availiable

This uses the new mailrc functionality to actually convert names!
Have show look up addresses in the mailrc

This is pretty much just a pretty printer... :)
Have "next" and "prev" actually move around

This isn't actually implemented correctly: these should be atomic.
I'm not entirely sure _what_ should be atomic, though: specifically,
should showing the message and incrementing be atomic?  That appears
to allow a very large window, which I don't really like.

I think the best thing to do is probably to have some notion of an
abortable transaction, but that's going to require digging through the
SQL documentation to see what's supported and I don't have internet
access right now.