Add dlib face point detector

[lunzhang]

This is a quick add of dlib face point detector

[lunzhang]

#35

[lunzhang]

The function face_points_2 works, how you want to use it, is up to you. Note - small mistake in the try and catch function with the except returning points instead of face_points

[alyssaq]

I couldnt merge it to master as the landmarks file was too huge. A workaround would be to have a post-script download the file during the pip install. For now, if anyone wants to try it out, its in the dlib branch in this repo. You'll have to download shape_predictor_68_face_landmarks.dat from http://dlib.net/files and place it in /facemorpher/data/