code: function loadTemplate(template, name, callback) {
    async.waterfall([
      cb => source(template.path, template.filter, template.readMode, cb),
      (files, cb) => asDataMap(files, template.mapping, cb),
    ], (error, result) => {
      async.nextTick(callback, error, result);
    });
  }
docs: Load a single template.