This replicates the c++ example.

new example code into face_detector.py and added some comments.

available in python3.

Also just cleaned up a few minor details.

A little bit hacky, but should be fine. Supports both fhog
detectors and the "cached" simple_object_detector. Also, maintains
the upscale parameter for testing

directly on already loaded data rather than needing to use an XML file as
input.

failure in the makedocs script