Fix dlib tests for c++11

c++11 std::mutex clashes with dlib::mutex when:

using namespace std;
using namespace dlib;

macros compile when invoked outside dlib namespace.

has a timeout parameter, so the connect() call should use that rather than
adding another.

rendering problem in perspective_display that appeared when drawing lines on
displays that weren't positioned at the upper left corner of the entire window.

used with objects that have non-square bounding boxes.  This has been fixed but
will cause models that were trained with the previous version of dlib to not
work as accurately if they used non-square boxes.  So you might have to retrain
your models when updating dlib.

by holding shift and right clicking and dragging.

new example code into face_detector.py and added some comments.

Merge branch 'py_det_conf_and_idx' of https://github.com/jackculpepper/dlib into jackculpepper-py_det_conf_and_idx

images.

the build more robust against name conflicts from other libraries that also
statically compile libjpeg or stick incompatible versions of libjpeg's header
files into folders in the include search path.

available in python3.

make the window show itself.