PyX update for Fedora 23 and rawhide just supports python 3

[José Abílio Matos]

I will update PyX, a Python graphics package, to version 0.14.

Since version 0.13, released in December of 2013, that PyX transitioned from python 2 to
3.

So the new version (and version 0.13 before) only supports python 3, while version 0.12
was a strict python 2 version.

The update will be pushed to f23+.

Regards,
-- 
José Abílio