constructor(opts={}) {
    super(opts);
    this.msg = opts.message;
    this.value = !!opts.initial;
    this.active = opts.active || 'on';
    this.inactive = opts.inactive || 'off';
    this.initialValue = this.value;
    this.render();
  }
TogglePrompt Base Element
@param {Object} opts Options
@param {String} opts.message Message
@param {Boolean} [opts.initial=false] Default value
@param {String} [opts.active='no'] Active label
@param {String} [opts.inactive='off'] Inactive label
@param {Stream} [opts.stdin] The Readable stream to listen to
@param {Stream} [opts.stdout] The Writable stream to write readline data to