[imp] Full IMAP support

[Mike Cochrane]

> ----- Message from enno_schulz at gmx.net ---------
>
> Hi,
> Is there anybody who has a working configuration or customized version
> of IMP that uses only the IMAP Server to store all the email-data in the
> IMAP databases on the serverside?
>

If I understand what you're saying. No one has written a driver to store
preferences on the user's IMAP server, this could be done with only a couple of
extra hits on the IMAP server every page request.

I doubt if a categories driver could be implemented effeciently using IMAP
storage.

- Mike :-)