The three new functions:

```cpp
void cvStartWriteRawData_Base64(::CvFileStorage * fs, const char* name,
int len, const char* dt);
void cvWriteRawData_Base64(::CvFileStorage *
fs, const void* _data, int len);
void
cvEndWriteRawData_Base64(::CvFileStorage * fs);
```

Test is also updated. (And it's remarkable that there is a bug in
`cvWriteReadData`.)

```cpp
cvWriteMat_Base64(::cv::FileStorage & fs, ::cv::String const & name,
::cv::Mat const & mat)
```
becomes:
```cpp
CV_EXPORTS void cvWriteMat_Base64(::CvFileStorage* fs, const char* name,
const ::CvMat* mat);
CV_EXPORTS void
cvWriteMatND_Base64(::CvFileStorage* fs, const char* name, const
::CvMatND* mat);
```

Two test are still needed:

1. Verify the Base64 data.
2. Read an old YML file for compatibility test.

Two other test are still needed.

1. Verify the Base64 data.
2. Read an old YML file for compatibility test.

[GSoC] FileStorage:
Add base64 support for reading and writting XML\YML file.
The two new functions:
```
void cvWriteRawData_Base64(cv::FileStorage & fs, const void* _data, int
len, const char* dt);
void cvWriteMat_Base64(cv::FileStorage & fs, cv::String const & name,
cv::Mat const & mat);
```

at least it is possible to read/ write calibration files. Fixes #4282.

Also add CPP method for writing comments.

All of these: (performance) Prefer prefix ++/-- operators for non-primitive types.
[modules/calib3d/src/fundam.cpp:1049] -> [modules/calib3d/src/fundam.cpp:1049]: (style) Same expression on both sides of '&&'.

Added a writeFormat() method to Algorithm which must be called by the
write() method of derived classes.

- added HAL documentation support
- added documentation to HAL replacement interface
- updated several HAL functions in imgproc module

typo correction

Apple OpenCL framework hasn't OpenGL sharing extension

Wrap in a cudaSafeCall.

Ensure the Cuda context is initialized correctly as long as the setDevice is not called in a multi-thread environment.

_sizes can point to internal structure which is destroyed
by release() call