code: function registerPartial(filepath, callback) {
      fs.readFile(filepath, 'utf8', function (err, data) {
        if (err) callback(err);
        hbs.registerPartial(path.parse(filepath).name, data);
        callback(null);
      });
    }
docs: Read file into buffer and register as hbs partials
  @param {String} filepath
  @param {Function.<Error>} callback