Test for augmenting pxd files

This project is just for me to test how to use cython to generate an extension from a pure python module with the use of an augmenting pxd file as described here: http://docs.cython.org/src/tutorial/pure.html#augmenting-pxd

I would like to be able to do this as it seems like a good way to maintain a pure python module along with a cython accelerated version.

Download and run::

$ python setup.py build_ext --inplace
$ python test.py

The output I get::

$ python test.py
Timings for the different implementations:
Pure python : 243.88935674 ns per loop iteration
Pure cython : 1.29719247757 ns per loop iteration
Augmenting  : 199.397050087 ns per loop iteration