load(path) {
    var resolved = this.resolve(path);

    if (this.archived) {
      return this.archive.request(resolved);
    } else {
      return this.request(resolved, null, this.settings.requestCredentials, this.settings.requestHeaders);
    }
  }
Load a resource from the Book
@param  {string} path path to the resource to load
@return {Promise}     returns a promise with the requested resource