Converting Country Names/Codes

Convert full name to two-digit ISO code:

<?php
$converter = new \RocketShipIt\Helper\CountryConverter;
$converter->fullToTwoDigit('United States'); // return 'US'
$converter->fullToTwoDigit('Afghanistan'); // 'AF'
$converter->fullToTwoDigit('Sweden'); // 'SE'
$converter->fullToTwoDigit('sweden'); //case is insensitive