VAT breaks amount

When VAT was added to an order, the amount was wrong and caused a Netbanx error. I added a round() to fix it.

'nbx_payment_amount' => round($order->order_total * variable_get('uc_netbanx_currency_factor', 100)),

The amount I was previously getting was 1420.55 instead of 1421.

No time to patch, I'm afraid! Sorry!