code: function render(drizzleData) {
    return Promise.all([
      renderPages(drizzleData),
      renderCollections(drizzleData)
    ]).then(
      allData => {
        return {
          data: drizzleData.data,
          pages: allData[0],
          patterns: allData[1],
          templates: drizzleData.templates,
          options: drizzleData.options,
          tree: drizzleData.tree
        };
      },
      error => DrizzleError.error(error, drizzleData.options.debug)
    );
  }
docs: Render pages and pattern-collection pages.
  
  @param {Object} drizzleData  All data built so far
  @return {Promise} resolving to drizzleData