Python C-API example uses the new Numpy Iterator protocol

Rewrote the Python C-API example to uses the NumPy iterator interface introduced in NumPy 1.6.  As per section 2.12.8.1 you might want a look.  

The reference counting probably needs work, but I'm getting the correct answers with EPD 7.3.2 and NumPy 1.6.1

Also thanks for these notes, they have been very helpful!