Add percentages by country and postal co

for osCommerce Online Merchant v2.2

Allow to add a percentage to total order amount by country / postal code. Useful to Spanish IVA: Add 16% to all states except all postal codes beginning with 07 (Palmas), 35 (Canarias), 38 (Tenerife), 51 (Ceuta) or 52 (Melilla). Verified in 2.1 and 2.2-CVS