Update keywords to show up in finder.

Update keywords to show up in finder.
(browse-url-gnudoit-args, browse-url-generic-program)
(browse-url-gnudoit-program, browse-url-generic-args): New variables.
(browse-url-w3-gnudoit): New procedure.
(browse-url-mmm): New location of `remote' file for MMM 0.4.
(browse-url-generic): New procedure.

(browse-url-netscape): Test for w32.

(browse-url-url-at-point): Assume mailto: if URL contains @.
Don't use thingatpt; find the URL here to do it correctly.

(browse-url-at-point, browse-url-of-file, browse-url-at-mouse):
Call browse-url.
(browse-url): Check for list browse-url-browser-function.
(browse-url-choose-browser): New procedure.
(browse-url-browser-function): Allow list value.

(browse-url-process-environment): Call browse-url-emacs-display.
(browse-url-emacs-display): New procedure.
(browse-url-netscape-display): New variable.

(browse-url-of-region): New procedure.
(browse-url-of-buffer): Check for narrowed buffer.

(browse-url-url-at-point): Rewrite to not use cl.el delete-if.
Fix multi-line URL matching.

(browse-url-markedup-regexp): New variable.
(browse-url-xterm-program): New variable.
(browse-url-xterm-args): New variable.
(browse-url-lynx-xterm): Use the above two vars.
(browse-url-url-at-point): Use buffer-substring-no-properties.
(browse-url-grail): Add missing optional arg.
(browse-url-mmm): New procedure.

(browse-url-netscape-startup-arguments): New variable.