Adds support for multiple faces.
Adds support for multiple faces.

Now grabs all faces found in an image, not just the first one.

watson-developer-cloud/visual-recognition-nodejs,oremari/plantDiseaseSymptoms-vr-demo-1483744992341,oremari/plantDiseaseSymptoms-vr-demo-1483744992341,watson-developer-cloud/visual-recognition-nodejs