Fixes Bug with number rounding

[MarkusHolstein]

Q	A
Branch?	1.6 (and above)
Bug fix?	yes
New feature?	no

Und certain circumstances the rounding in PHP runs wild. This leads to a problem, when trying to validate the amount sent to paypal vs. the amount of the cart.

Example:

$totalAmount = 0;
$unit['amount']['value'] = '2258.45';

$stringAmount = $unit['amount']['value'] ?? '0';
$totalAmount += (int) ($stringAmount * 100);

var_dump($totalAmount);
var_dump($stringAmount * 100);

Results in

int(225844)
float(225844.99999999997)

Thus, the value needs to be rounded, before casting to int.

So some people are currently unable to use the paypal function of our website.