code: function addFeatureOption(name, kind) {
    if (kind === EXPERIMENTAL)
      experimentalOptions[name] = true;
  
    Object.defineProperty(parseOptions, name, {
      get: function() {
        return !!options[name];
      },
      enumerable: true,
      configurable: true
    });
  
    Object.defineProperty(transformOptions, name, {
      get: function() {
        var v = options[name];
        if (v === 'parse')
          return false;
        return v;
      },
      enumerable: true,
      configurable: true
    });
  
    var defaultValue = options[name] || kind === ON_BY_DEFAULT;
    options[name] = defaultValue;
    defaultValues[name] = defaultValue;
  }
docs: Adds a feature option.
  This also adds a view from the parseOption and the transformOption to the
  underlying value.