docs(README): add notice for extra elements support & limitations

Author: thgreasi

README.md

@@ -43,9 +43,9 @@ Apply the directive to your form elements:
 **Developing Notes:**
 
 * `ng-model` is required, so that the directive knows which model to update.
-* `ui-sortable` element should only contain one `ng-repeat` and not any other elements (above or below).  
-  Otherwise the index matching of the generated DOM elements and the `ng-model`'s items will break.  
-  **In other words: The items of `ng-model` must match the indexes of the generated DOM elements.**
+* `ui-sortable` element should contain only one `ng-repeat`, but other non-repeater elements above or below may still exist.
+  Otherwise the index matching of the `ng-model`'s items and the DOM elements generated by the `ng-repeat` will break.  
+  **In other words: The items of `ng-model` must match the indexes of the DOM elements generated by the `ng-repeat`.**
 * `ui-sortable` lists containing many 'types' of items can be implemented by using dynamic template loading [with ng-include](http://stackoverflow.com/questions/14607879/angularjs-load-dynamic-template-html-within-directive/14621927#14621927) or a [loader directive](https://github.com/thgreasi/tg-dynamic-directive), to determine how each model item should be rendered. Also take a look at the [Tree with dynamic template](http://codepen.io/thgreasi/pen/uyHFC) example.
 
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