Remote usage script updated

[Jesse Rosenthal]

Dear all,

Just a note to say that I finally got around to updating the remote
usage script on the wiki to what I'm using now. With "--format=raw" in,
it's all pretty straightforward. The only things the script does now
are:

1. Produces a slight pause in the "notmuch show" output to avoid that
   weird bug where emacs leaves off every tenth message or so.

2. Locally caches raw messages (i.e. when --format=raw) is called. This
   usually happens when getting attachments, so this is a nice way to
   avoid having to download large attachments repeatedly.

   Note this just caches based on msg-id (or a hash thereof, to avoid
   strange characters in file names). That means that if an attachment
   is deleted on the server, the cache will be out of date. An easy way
   to fix this would be to make the cache file name a concatenation of
   the msg-id hash (check that first) and the hash of the actual message
   (check that if the msg-id hash is there). I might put this in in the
   future, especially if anyone else is using the script.

3. Escapes dollar signs in the msg-id to make shell-quoting over ssh
   work.

I've actually switched over to keeping my messages on my IMAP server and
using this remote script on all of my computers. It avoids any need for
syncing. It's been working very well for me so far.

A future feature might be to integrate the ControlMaster feature of
openssh into the script, instead of having to open a connection
manually, but there are some complications there (dead sockets still
around if you go offline, etc.).

Best,
Jesse