Links for PyX

https://downloads.sourceforge.net/project/pyx/pyx/0.12.1/PyX-0.12.1.tar.gz#md5=04263eb002553dae0e8a1d0eeb805ec1
https://downloads.sourceforge.net/project/pyx/pyx/0.13/PyX-0.13.tar.gz#md5=aeda519f5b3f118a9c940c82758489d0