www/rubygem-rqrcode_core: New port

rqrcode_core is a library for encoding QR Codes in pure Ruby. It has a
simple interface with all the standard qrcode options. It was originally
adapted in 2008 from a Javascript library by Kazuhiko Arase.

Features:

• rqrcode_core is a Ruby only library. It requires no 3rd party libraries. Just Ruby!
• It is an encoding library. You can't decode QR Codes with it.
• The interface is simple and assumes you just want to encode a string into a QR Code, but also allows for encoding multiple segments.
• QR Code is trademarked by Denso Wave inc.

rqrcode_core is the basis of the popular rqrcode gem. This gem allows
you to generate different renderings of your QR Code, including png, svg
and ansi.

Sponsored by: Nepustil