* riece-misc.el (riece-get-identities-on-server): New function.

(riece-get-users-on-server): Use it.

* riece-ctcp.el (riece-ctcp-completing-read-identity): Abolish.
(riece-command-ctcp-version): Use riece-completing-read-identity
and riece-get-identities-on-server.
(riece-command-ctcp-ping): Ditto.
(riece-command-ctcp-clientinfo): Ditto.
(riece-command-ctcp-action): Ditto.

* riece-commands.el (riece-command-finger): Pass the current
server name to riece-get-users-on-server; use
riece-completing-read-identity.
(riece-command-invite): Ditto.
(riece-command-enter-message-to-user): Ditto.

* riece-000.el (riece-handle-001-message): Register myself with
riece-obarray.