Fixed setup.py to be compatible with upcoming Cython 0.13 release.
Fixed setup.py to be compatible with upcoming Cython 0.13 release.

There was a small bug in the way we turn on annotations in the setup.py
script; this has been corrected.

nyee/RMG-Py,pierrelb/RMG-Py,enochd/RMG-Py,faribas/RMG-Py,comocheng/RMG-Py,nickvandewiele/RMG-Py,KEHANG/RMG-Py,nickvandewiele/RMG-Py,faribas/RMG-Py,chatelak/RMG-Py,enochd/RMG-Py,comocheng/RMG-Py,chatelak/RMG-Py,KEHANG/RMG-Py,nyee/RMG-Py,pierrelb/RMG-Py