feat #  prototype for section refresh animation

implementation of the section refresh animation
Instead of directly setting `innerHTML`, it is perhaps better to call `aria.utils.Dom.replaceHTML` which works around some problems in IE with table elements. It can potentially return a new DOM element, so it should be used in the following way:
```js
this._newSection = aria.utils.Dom.replaceHTML(this._newSection, this.html);
```