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

* Add functionality to filter homography decompositions

* documentation + small refactor

* fix comparing int to size_t (compiler warning)

* fix whitespace issues

* clarification of function return values in documentation

* refactor of function parameters and change in loop nesting

* cleanup useless .h, fix size_t to int compare, small refactor

* fix documentation and whitespace

* change output from return value to outputarray parameter

* update function docs to reflect changes in parameters

* whitespace

* failing test

* fixed warnings related to extended initialisers and improper types

* initialize vectors from arrays

* initialize vectors from arrays part 2

* fix whitespace

* fix trailing whitespace

* Include <inttypes.h> in test_filter_homography_decomp.cpp, should fix 'uint8_t' : undeclared identifier error

* updated the test (made it shorter and providing better diagnostic) and significantly improved implementation (get rid of heavy repeated and/or unnecessary operations)

* fixed compile warning; removed trailing whitespace

* Pass RANSAC parameters as function input

* Clean up unnecessary code

* Keep the original function signature

* Clean up based on PR comments

Replace array with vector.

Correct naming convention for input variables.

Add checks on input variables.

* Use vector instead of array for dynamic size

* Revert change.

* Use dynamic array

* Fix wrong syntax in array allocation

* Undo change

* Fix variable name

* Use vector and not array

* fixed compile warning on Windows

* temporarily disabled OpenCL use in DNN module on Mac, since some of the tests fail

* disable OpenCL in DNN on Mac at CMake level, not source level (thanks to alalek for the advice)

* optimize ocl kernel enqueue in fc layer
Signed-off-by: Li Peng <peng.li@intel.com>

* use CV_LOG_INFO in convolution auto tuning
Signed-off-by: Li Peng <peng.li@intel.com>

* update convolution IDLF kernel

extend parameter tuning range, also cleanup
ocl kernel implementation
Signed-off-by: Li Peng <peng.li@intel.com>

* update in-memory convolution cache config

fp16 and fp32 cache config are stored separately
Signed-off-by: Li Peng <peng.li@intel.com>

* apps: add Win32 friendly opencv_version app

Improve experience of launching app from explorer:
- application just flash (open/close) the console window
Suggested Win32 application flavor additionally shows MessageBox
and waits for User interaction.

* cmake: added unified application creation function

* Kinect2 support added to OpenNI2 backend

* more fixes for OpenNI2 backend

* whitespace fixed

* libfreenect2 support added

* const cast added

* mutable removed

OPENCV_OCL4DNN_FORCE_AUTO_TUNING should ignore existed configuration from:
- builtin predefined configurations (for Intel OpenCL iGPUs)
- external configuration (via OPENCV_OCL4DNN_CONFIG_PATH)

Prefer external configuration over builtin.

`dest(roi_d)` operation contains similar check inside.