Update Py3 references in the Pyrex comparison.
Update Py3 references in the Pyrex comparison.

scoder/cython,scoder/cython,cython/cython,cython/cython,cython/cython,da-woods/cython,scoder/cython,cython/cython,da-woods/cython,da-woods/cython,scoder/cython,da-woods/cython