Adopt RFC2822 for `References' and `In-Reply-To' field.

Adopt RFC2822 for `References' and `In-Reply-To' field.
(message-yank-add-new-references): Change initial value to nil instead of t.
(message-header-format-alist): Format `In-Reply-To' field as same as
`References' field.
(message-yank-original): Add message id to `In-Reply-To' field instead of
`References'.
(message-replace-reference): New function.
(message-make-in-reply-to): Return only `Message-Id'.
(message-reply): Insert `In-Reply-To' field.