void setRole(Role newRole)
    {
        role = newRole;
        synchronized (this) {
            if (Role.none == role) {
                presence.setType(Presence.Type.unavailable);
                presence.setStatus(null);
            }
            calculateExtendedInformation();
        }
    }
Call this method to promote or demote a user's role in a chatroom.
It is common for the chatroom or other chat room members to change
the role of users (a moderator promoting another user to moderator
status for example).

Owning ChatUsers should have their membership roles updated.

A role is a temporary position or privilege level within a room, distinct from a user's long-lived affiliation
with the room. A role lasts only for the duration of an occupant's visit to a room.

@param newRole The new role that the user will play.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/MUCOccupant.java