Base64 encode or decode fields using Perl instead of Python

A Perl version of Cedric Le Roux base64 encode/decode. A limitation exists in Base64 Python lib that made me develop this Perl version: it does not handle padding the right way. This Perl version provides two advantages over the Python version: - speed: about 2x faster thanks to Text::CSV_XS Perl module - padding: don't worry about padding issues anymore