Changes:
* w3m.el (w3m-delete-buffer): Switch to the previous emacs-w3m buffer
explicitly; bind frame-auto-delete and ignore-window-parameters while
killing the buffer.
(w3m-goto-url): Change the order of retrieving group:* urls so as to
arrange the buffer list in turn.
* w3m.el (w3m-goto-mailto-url): Pass other headers to the agent.
* w3m-ems.el (w3m-toolbar-define-keys): Work around the Emacs 24 error
"`keymap' is reserved for embedded parent maps".
* w3m.el (w3m-content-type-alist): Use functionp instead of symbolp for
the users who set their own private function to
browse-url-browser-function.
* w3m.el (w3m-content-type-alist): When selecting which external html
browser to use, handle the case where browse-url-browser-function is
an alist.
* w3m.el (w3m-goto-mailto-url): Decode entities in URL.
