Found via `codespell -q 3 -S ./3rdparty,./modules -L amin,ang,atleast,dof,endwhile,hist,uint`

backporting of commit: 32aba5e6

Detailed description for my proposal can be found here
https://github.com/opencv/opencv/issues/14128

* Add flushing to printing number of processed positive/negative samples so that user is informed of updates quickly.

* use flush C api instead of C++ api

backport 997b7b18

Relevant guards can be found in
https://github.com/opencv/opencv/blob/ef5579dc8667e5eb5e149acc4af898421eed99da/modules/features2d/src/kaze/AKAZEConfig.h#L8
and
https://github.com/opencv/opencv/blob/ef5579dc8667e5eb5e149acc4af898421eed99da/modules/ml/include/opencv2/ml.hpp#L44

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

* 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

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.

- build "opencv_version" only: `cmake -DBUILD_APPS_LIST=version ...`
- option 'BUILD_opencv_apps' should be 'ON'

destroyWindow was called twice during completion of the
annotation procedure, resulting in a crash, and failure to write
an output file

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

fix missing "opencv2/core/opencl" headers from core module (updated install list)

* update createsamples

adds command-line option -rngseed
replaces rand() -> theRNG()

* Update utility.cpp

* apps(createsamples): fix warpPerspective pixels access bug

Implementation of bit-exact resize. Internal calls to linear resize updated to use bit-exact version. (#9468)

Added a couple of comments to the interface of traincascade.cpp in order to tell user about the usage of traincascade.cpp file and to learn how Github submitting works

(2.4) Backports from master branch (#7854)