Synch with Oort Gnus.

Synch with Oort Gnus.

* gnus-sum.el (gnus-article-commands-menu): Bind "Html" to the command
 `gnus-article-wash-html'.
(gnus-summary-article-menu): Ditto.
(gnus-summary-wash-map): Bind "h" to the command `gnus-article-wash-html'.

* gnus-art.el (gnus-article-treatment-menu): Bind "Treat html" to the command
 `gnus-article-wash-html'.

* nnheader.el: Place mm- stuff and mail-parse stuff in front of the codes
 which use (or may use) them.