Install OpenCV via build, as per: http://www.pyimagesearch.com/2015/06/15/install-opencv-3-0-and-python-2-7-on-osx/
If you're using conda, the second (unaccepted) answer here worked to install without building:
conda remove opencv conda install -c menpo opencv pip install --upgrade pip pip install opencv-contrib-python
Or, conversely, use python pip -r requirements.txt from within this directory (although you may be unable to show images in an IDE if you don't build from source).
find_features.py should work with any directory of images that you pass it to demonstrate OpenCV's classifiers. measure_distance.py requires a bit more setup, with a reference image and reference object within that image to triangulate position of faces detected relative to the camera. The examples in examples/distance/out/ show the result of this file.