lintString(text, options) {
    return this._parseString(text, options)
      .then(this._lintTree.bind(this))
      .then(errors => {
        errors.forEach(error => {
          error.context = this._getContext(text, error.line);
        });

        return errors;
      });
  }
Lints a string.

@param {String} text
@param {{context: String, filename: String, syntax: String}} options
@returns {Promise} Resolves with <Array> list of found errors.