setupOrRemovePortListeners(onOrOff) {
    let port = this.port;
    let messages = this.messages;

    for (let name in messages) {
      if (messages.hasOwnProperty(name)) {
        port[onOrOff](this.messageName(name), this, messages[name]);
      }
    }
  }
Setup or tear down port listeners. Call on `init` and `willDestroy`
@param {String} onOrOff 'on' or 'off' the functions to call i.e. port.on or port.off for adding or removing listeners