* elmo-pop3.el (toplevel): Require elmo-map.

* elmo-pop3.el (toplevel): Require elmo-map.
(elmo-pop3-folder): Inherit elmo-location-map and abolish
location-alist slot (All other related portions are changed).
(elmo-pop3-folder-use-uidl): New function.
(elmo-folder-msgdb-create): Don't sort message entities.
(elmo-pop3-sort-msgdb-by-original-number): Abolish.
(elmo-pop3-number-to-size): Convert return value to number.
(elmo-pop3-msgdb-create-by-header): Use unwind-protect to delete a
working buffer.

* elmo-map.el: Use `location-map' as a variable name for instance
instead of `mapper'.
(elmo-location-map-setup): Return location alist.
(elmo-location-map-update): Ditto.