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

- removed tr1 usage (dropped in C++17)
- moved includes of vector/map/iostream/limits into ts.hpp
- require opencv_test + anonymous namespace (added compile check)
- fixed norm() usage (must be from cvtest::norm for checks) and other conflict functions
- added missing license headers

* Remove "simple" flow estimation from help (because it was disabled by 653bca8b)
* Add `flush` after printing iteration number for better UX

compute() for BP and CSBP output 32-bit floating-point mat, and in cv::imshow() 32-bit floating-point is recognized as [0,1] and maped to [0,255], that causes gray window for BP and CSBP.

Original commit is a5f19f7dd6ae5bc93f73e0417a9e0bfd34c01672

in this case the sample will not be built if OpenGL is not found

(cherry picked from commit ff002203)

As is it was not possible to use CUDA.

changed hog to work with variable parameters and changed the hog sample to test it with more options

added comments and tests

Conflicts:
	samples/gpu/video_writer.cpp