code: function listBlocks(plugins) {
      return plugins
          .reverse()
          .reduce(function(result, plugin) {
              var blocks = plugin.getBlocks();
              return result.merge(blocks);
          }, Immutable.Map());
  }
docs: List blocks from a list of plugins
  
  @param {OrderedMap<String:Plugin>}
  @return {Map<String:TemplateBlock>}