Vathandler

Here is the vatHandler. Seems to be working. 
Some things to note
* I needed to change converter because we were dealing with dataText[0] for the isVatIncluded thing, but that value is not the first but the second. 
* Fixed some tests too after the change of array $price to PriceValue $price

Still to do, add some exception for the Automatic Vat Handling.