Request a resource (file or directory).

@param {string} path - Path of the resource
@param {Object} options - Request options
@returns {Promise} Resolves with an object containing the status code,
body, content-type and revision

@protected
function (path, options) {
    if (path.substr(-1) === '/') {
      return this._getFolder(googleDrivePath(path), options);
    } else {
      return this._getFile(googleDrivePath(path), options);
    }
  }