* mixi.el (mixi-object-p): Check whether class is symbol.

* mixi.el (mixi-object-p): Check whether class is symbol.
(mixi-read-object): New function.
(mixi-cache-file-regexp): New regexp.
(mixi-cache-regexp): Use it.
(mixi-save-cache): Remove the prefix of file name.
(mixi-read-cache): Use `mixi-read-object' instead of `puthash'.
(mixi-load-cache): Follow the change above.
(mixi-make-friend): Add all slots to the argument.
(mixi-make-diary): Ditto.
(mixi-make-community): Ditto.
(mixi-make-topic): Ditto.
(mixi-make-event): Ditto.
(mixi-make-message): Ditto.