* face recognition with knn

* improved knn, added doc and tests

* updated for flake8

* fixed requirements

* fixed paths in test

* fixed additional paths in test

* updated tests

* updated readme

* Add recognition with k-nearest-neighbors classifier

* Correcting for PR comments

* remove scikit-learn from global requirements

* remove scikit-learn from setup requirements

* Add intro to knn example

* Support dlib 19.7 changes

* Typo fix

* README update

Add support for dlib's new cnn-based face detector