* riece-identity.el (riece-identity-member): Take an optional 3rd

* riece-identity.el (riece-identity-member): Take an optional 3rd
argument to instruct to use riece-identity-equal-no-server.
(riece-identity-assoc): Ditto.

* riece-display.el (riece-update-user-list-buffer): Use
riece-channel-operator-p and riece-channel-speaker-p.

* riece-button.el (riece-user-button-set-operators): Use
riece-channel-operator-p.
(riece-user-button-set-speakers): Use riece-channel-speaker-p.

* riece-channel.el (riece-channel-intern-user): New function.
(riece-channel-toggle-operator): Use it.
(riece-channel-toggle-speaker): Use it.
(riece-channel-operator-p): New function.
(riece-channel-speaker-p): New function.