[notmuch] JSON based emacs UI

[David Edmondson]

I'm pushed the first stage of a JSON based emacs UI to the repository at
http://github.com/dme/notmuch (it's in the "master" branch).

This is intended to be functionally equivalent to the current UI, though
HTML display is not present (see below).

This is lightly tested, but if anyone else wants to give it a try I
would be interested in feedback. There were a couple of places in the
current code where I wasn't completely sure of the intention, so I may
have inadvertently diverged (notmuch-show-rewind is a good example).

For HTML display and other improved MIME support my intention is to
enhance notmuch to allow single parts to be output (something like:
"notmuch show --part=2 id:k74hf87df.fsf at fish.org") and use that from the
UI code. No idea when I'll get to it, though.

Carl - the main changeset is large, but I couldn't see a sensible way to
break it up into smaller pieces. I'm open to suggestions.

Finally, if anyone else is working on something like this, please let me
know - I'd be interested in collaborating.

ps. Thanks to aep in #notmuch for encouraging me to just get on with it.

dme.
-- 
David Edmondson, http://dme.org