* Fixed reference count issue

* Fixed refcount issue in Python dlib.jitter_image and dlib.get_face_chips

* Consolidation of https://github.com/davisking/dlib/pull/1249

* Fixed build issue

* Fixed: Paths in a pytest file should be relative to dlib root

* Skip numpy return tests for Python 2.7 or if Numpy is not installed

* Enabled numpy returns tests on Python 2.7 using cPickle.dumps

In particular, these new functions don't need to be inside the face
recognition class.  So I moved them out.  I also fixed many incorrect
copy/pasted comments and clarified parts of the example code.