Character encoding support

All thanks to our brilliant contributors, @kevinsearle and @vatri for introducing the character encoding and handling support.

Originally @vatri raised the problem (#13) after facing it in one of the projects using this library and @kevinsearle came forward with the prompt solution (#14).

Well done both! 💯

Example:

$csv = new CSV_Parser();
$csv->setEncoding('ASCII');
$csv->encode();

$encodedData = $csv->getData();