* elmo-vars.el (elmo-default-pop3-authenticate-type):

* elmo-vars.el (elmo-default-pop3-authenticate-type):
Set default as 'user.

* mmelmo-imap4-2.el (mmelmo-imap4-get-mime-entity): Rewrite.

* elmo2.el (elmo-quit): Don't use `elmo-pop3-flush-connection'
and `elmo-imap4-flush-connection'.

* elmo-util.el (toplevel): Removed workaround for timezone y2k.
(elmo-pop3-get-spec): Assume auth as symbol.
(elmo-open-network-stream): Moved to `elmo-net'.

* elmo-pop3.el (toplevel): Require 'elmo-net.
Define `sasl-cram-md5' to silence byte compilier.
(elmo-pop3-connection-cache) Abolished.
(elmo-pop3-authenticator-alist) New variable.
(elmo-pop3-session): Define.
(elmo-pop3-connection-get-process): Abolished.
(elmo-pop3-connection-get-buffer): Ditto.
(elmo-pop3-close-connection): Ditto.
(elmo-pop3-flush-connection): Ditto.
(elmo-pop3-get-connection): Ditto.
(elmo-pop3-get-session): New function.
(Replacement for `elmo-pop3-get-connection').
All other related modules are changed.
(elmo-network-close-session): Define.
(elmo-pop3-send-command): Abolished argument `buffer'.
All other related modules are changed.
(elmo-pop3-read-response): Likewise.
(elmo-pop3-open-connection): Abolished.
(elmo-pop3-auth-user): New function.
(elmo-pop3-auth-apop): Ditto.
(elmo-pop3-auth-cram-md5): Ditto.
(elmo-pop3-auth-scram-md5): Ditto.
(elmo-pop3-auth-digest-md5): Ditto.
(elmo-network-initialize-session): Define.
(elmo-network-authenticate-session): Ditto.
(elmo-network-setup-session): Ditto.

* elmo-imap4.el (toplevel): Require 'elmo-net.
(elmo-imap4-session): Define.
(elmo-imap4-connection-cache): Abolished.
(elmo-imap4-password-key): Ditto.
(elmo-imap4-flush-connection): Ditto.
(elmo-imap4-get-connection): Ditto.
All other related modules are changed.
(elmo-imap4-get-session): New function
(Replacement for `elmo-imap4-get-connection').
(elmo-imap4-read-response): Abolished argument `buffer'.
All other related modules are changed.
(elmo-imap4-send-command): Likewise.
(elmo-imap4-select-folder): Abolished.
All other related modules are changed.
(elmo-imap4-select-mailbox): New function.
(Replacement for `elmo-imap4-select-folder').
(elmo-imap4-auth-login): Simplify.
(Assume current buffer as process buffer)
(elmo-imap4-auth-cram-md5): Ditto.
(elmo-imap4-auth-digest-md5): Ditto.
(elmo-imap4-login): Ditto.
(elmo-imap4-open-connection): Abolished.
(elmo-imap4-open-connection-1): Abolished.
(elmo-network-initialize-sessoin): Define.
(elmo-network-authenticate-session): Ditto.
(elmo-network-setup-session): Ditto.

* elmo-net.el: New module.