* fixed#17044
1. fixed Python part of the tutorial about using OpenCV XML-YAML-JSON I/O functionality from C++ and Python.
2. added startWriteStruct() and endWriteStruct() methods to FileStorage
3. modifed FileStorage::write() methods to make them work well inside sequences, not only mappings.
* try to fix the doc builder
* added Python regression test for FileStorage I/O API ([TODO] iterating through long sequences can be very slow)
* fixed yaml testing
Updated the Windows Visual Studio Image Watch tutorial to include download links to the latest versions of Visual Studio Image Watch for newer Visual Studio versions.
The PREDEFINED setting for had a space between the define name and the equal sign and this is not allowed, it results in the warning:
```
error: Illegal PREDEFINED format '=', no define name specified
```
according to the documentation explicitly states that no space is allowed:
> The PREDEFINED tag can be used to specify one or more macro names that are defined before the preprocessor is started (similar to the -D option of e.g. gcc). The argument of the tag is a list of macros of the form: name or name=definition (no spaces). If the definition and the "=" are omitted, "=1" is assumed. To prevent a macro definition from being undefined via #undef or recursively expanded use the := operator instead of the = operator.
* Add python version of panorama_stitching_rotating_camera and perspective_correction
* Updated code
* added in the docs
* added python code in the docs
* docs change
* Add java tutorial as well
* Add toggle in documentation
* Added the link for Java code
* format code
* Refactored code
* Added java code for meanshift and optical_flow
* added java code for module video
* added appropriate spaces in codes
* converted absolute path to command line arguments
* added spaces at appropriate places
Python code examples for file IO in xml and yml format
* Initial "Pythonization" of file_input_output.cpp
* Moved file_input_output.py to correct location
* Nearly done Pythonizing file_input_output.cpp
* Python equivalent of file_input_output.py created
* Started Pythonizing camera_calibration.cpp
* Completed Python tutorial/sample code for file_input_output
* Resolved whitespace issues
* Removed tabs in file_input_output.cpp
* Patched import order and wrapped code in main function
* Changed string to docstring format in help file
* Updated link to Python example code
