code: function parsePageFromString(page, content) {
      // Parse page YAML
      var parsed = fm(content);
  
      return page.merge({
          content:    parsed.body,
          attributes: Immutable.fromJS(parsed.attributes),
          dir:        direction(parsed.body)
      });
  }
docs: Parse a page, its content and the YAMl header
  
  @param {Page} page
  @return {Page}