* Fixed reference count issue

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

* prevent C++ compilation flags leaking to CUDA

* disable compilation flags leak fix for old cmake on windows

* disable compilation flags leak fix for cmake older than 3.3

Improved the stopping condition of solve_qp_box_constrained() and solve_qp_box_constrained_blockdiag().