(rmail-label-obarray): Deleted.

(rmail-label-obarray): Deleted.
(rmail-attributes): Use an ordinary list of symbols.
(rmail-deleted-label): Use an ordinary symbol.
(rmail-keywords): Doc, initial value nil.
(rmail-keywords, rmail-keyword-init): Deleted defuns.
(rmail-attribute-p, rmail-keyword-p, rmail-make-label): Simplify.
(rmail-keyword-register-keywords, rmail-install-keyword):
Replaced.
(rmail-register-keywords, rmail-register-keyword): Replacements.
(rmail-add-label, rmail-kill-label): Call set-label with a symbol.
(rmail-read-label): Return a string.
(rmail-set-label): Rewrote. Call rmail-display-labels always.