Allow float amount

Thanks again for great plugin and great updates.
One of our needs is to add and reduce amount in float. it’s used for example to sell fruits in Kg.
I have changed the plugin’s code in order to access float amount. and it worked by changing some absint( $data[‘quantity’] ) to floatval( $data[‘quantity’] ) and change the type of amount from integer to float for update and add item.

It would be appreciated if you do this modification in new update.