code: function loadTemplate(template, plain) {
              if (!template) {
                return '';
              }
  
              if (angular.isString(template) && plain) {
                return template;
              }
  
              return $templateCache.get(template) || $http.get(template, { cache : true });
            }
docs: Load the given template in the cache if it is not already loaded.
  
  @param template The URI of the template to be loaded.
  @returns {String} A promise that the template will be loaded.
  @remarks If the template is null or undefined a empty string will be returned.