* riece.el (riece-command-mode): Set

* riece.el (riece-command-mode): Set
riece-mode-line-buffer-identification.
(riece-dialogue-mode): Ditto.
(riece-channel-mode): Ditto.
(riece-channel-list-mode): Ditto.
(riece-user-list-mode): Ditto.
* riece-icon.el
(riece-icon-update-mode-line-buffer-identification): New function.
(riece-icon-insinuate): Use it.
(riece-icon-uninstall): Use it.
* riece-globals.el (riece-mode-line-buffer-identification): New
variable.