Another improvement of MIME handling in rmail.

lisp/ChangeLog

+2011-01-12  Kenichi Handa  <handa@m17n.org>
+
+	* mail/rmailmm.el (rmail-mime-next-item)
+	(rmail-mime-previous-item): Delete them.
+	(rmail-mime-shown-mode): Recursively call for children.
+	(rmail-mime-hidden-mode): Delete the 2nd arg TOP.  Callers
+	changed.
+	(rmail-mime-raw-mode): Recursively call for children.
+	(rmail-mode-map): Change mapping of tab and backtab to
+	forward-button and backward-button respectively.
+	(rmail-mime-insert-tagline): Always insert "Hide" or "Show"
+	button.
+	(rmail-mime-update-tagline): New function.
+	(rmail-mime-insert-text): Call rmail-mime-update-tagline if the
+	body display is changed.
+	(rmail-mime-toggle-button): Renamed from rmail-mime-image.
+	(rmail-mime-image): Delete this button type.
+	(rmail-mime-toggle): New button type.
+	(rmail-mime-insert-bulk): Call rmail-mime-update-tagline if the
+	body display is changed.  Change the save button label to "Save".
+	Don't process show/hide button here.
+	(rmail-mime-insert-multipart): Call rmail-mime-update-tagline if
+	the body display is changed.  Unconditionally call
+	rmail-mime-insert for children.
+	(rmail-mime-handle): Update `display' vector of the just inserted
+	entity.
+	(rmail-mime-process): If mail-header-parse-content-type returns
+	nil, use "text/plain" as the fallback type.
+	(rmail-mime-insert): For raw-mode, recursively call
+	rmail-mim-insert for children.
+	(rmail-mime): Handle the case that the current buffer is not rmail
+	buffer (e.g. in summary buffer).
+
+2011-01-05  Kenichi Handa  <handa@m17n.org>
+
+	* mail/rmailmm.el (rmail-mime-next-item)
+	(rmail-mime-previous-item): Skip the body of a non-multipart
+	entity if a tagline is shown.
+
 2011-01-04  Kenichi Handa  <handa@m17n.org>
 
 	* mail/rmailmm.el (rmail-mime-insert-bulk): Display an unknown