implement schema.org aggregate rating

schema.org.html

<span itemprop="review" itemscope itemtype="http://data-vocabulary.org/Review-aggregate">
		<span itemprop="rating" style="display:none;">4</span>
		<span itemprop="count" style="display:none;">1</span>
</span>

<!-- SHOULD BECOME -->

<span itemprop="aggregateRating" itemscope itemtype="http://schema.org/AggregateRating">
		<span itemprop="ratingValue" style="display:none;">4</span>
		<span itemprop="reviewCount" style="display:none;">1</span>
		<meta itemprop="ratingCount" content="1" />
</span>

<!--
note: entire block should fall in http://schema.org/Product element 
Test the changes to HTML source with:
Google webmaster tools > Uiterlijk van Site Search > Gestructureerde gegevens > Product > (click a random Page-URL) > Live gegevens testen.
-->