* Add python api that generates desciptor(s) from the aligned image(s)

* Remove asserts from face_recognition.py example/tutorial

* In batch_compute_face_descriptors_from_aligned_images, use for-in loop to simplify the code

Improvde the document on binding methods and the error message if the aligned image is not of size 150x150

* Exposing chinese_whispers directly

* Addressing comments

* Changed description
* Added support for distance weights
* Added tests

* Improving test to check returned results

* added scale_image python binding which returns an image resized by the provided scale factor

* added scale_rect for rectangle and drectangle. returns a rectangle scaled by the provided scaling factor

* - do not cast scale_rect coordinates to long for drectangle
- document scale_rect for drectangle and rectangle in _abstract.h
- change python binding scale_image to resize_image
- update documentation for resize_image to describe behaviour

python API.

to the simple object detection objects in the Python API.

threshold_image().

object_detector constructor from python.  So now you can pack multiple
detectors into one object via the python API.

image_window in Python.

norm regularization stuff to Python. This also includes adding
num_separable_filters() and threshold_filter_singular_values() to the Python API.