[imp] contacts in IMP 2.2.5

[Paul Hancock]

> The addressbook in IMP 2.2 and earlier is ugly, inflexible, hackish,
> badly implemented, and uses the second sql table I ever designed in my life.
> This is largely why Turba was created and all of the old code completely
> dropped for IMP 2.3. If you really want to expand it, it's up to you.

On the other hand, it does some things that are not currently possible in the 
development tree, such as looking up addresses and adding To:, Cc:, and Bcc: 
recipients while in the compose window.