- Changing the contrast and brightness of an image!
      - Operations with images

Add Java and Python code for AKAZE local features matching tutorial. Fix incorrect uses of Mat.mul() in Java code.

Uniform Lowe's ratio test in the code.

Add Java and Python code for Image Segmentation with Distance Transform and Watershed Algorithm tutorial. Use more Pythonic code.

Add Java and Python code for the following imgproc tutorials: Finding contours in your image, Convex Hull, Creating Bounding boxes and circles for contours, Creating Bounding rotated boxes and ellipses for contours, Image Moments, Point Polygon Test.

Tested with:
- pylint 1.9.1

Add Java and Python code for the following features2d tutorials: Harris corner detector, Shi-Tomasi corner detector, Creating your own corner detector, Detecting corners location in subpixels, Feature Detection, Feature Description, Feature Matching with FLANN, Features2D + Homography to find a known object. Use Lowe's ratio test to filter the matches.

Add Java and Python code for the following imgproc tutorials: Affine Transformations, Histogram Equalization, Histogram Calculation, Histogram Comparison, Back Projection.

Add Java and Python code for the following imgproc tutorials: Canny, Remap, threshold and threshold inRange. Use HSV colorspace instead of RGB for inRange threshold tutorial.

* fix faster_rcnn sample crashed at PoolingInvoker operator() of pooling_layer.

* find_odj onmouse bug about find matched point status.

* reverted AutoBuffer back to std::vector

Found via `codespell -q 3 --skip="./3rdparty" -I ../opencv-whitelist.txt`

* hogsvm compatibility with python3

Update left_intrinsics.yml file with chessboard square_size=0.025 and with extrinsic parameters. Add camera_calibration_show_extrinsics.py, a Python sample that allows to display the extrinsics saved during the camera calibration process (cpp-example-calibration).

Fix a code indent bug:   cv2.imshow("detected lines", cdst)

Following were the errors in the digits_video.py
     1 ) The code was not working because data type of x was float however in "cv2.rectangle" we require integer .
     2 ) After pressing the "esc" button the image windows did not destroy
So I amended following things:
     1 ) ~converted data type of x to int.~ Used Python integer division (//)
     2 ) used cv2.destroyAllWindows() to close all windows after the press of "esc" by user.

* Adding threading in calibrate.py

* samples: update calibrate.py

* Unused variables
* Bad identation