(imap):

(imap):
(imap-kerberos4-program):
(imap-gssapi-program):
(imap-ssl-program): Customization.
(imap-shell-program):
(imap-shell-host): New variables.
(imap-streams):
(imap-stream-alist): Add shell.
(imap-shell-p):
(imap-shell-open): New functions.
(imap-open): Don't call authenticator if preauth.
(imap-authenticate): Return t if already authenticated.