- Use shfl_down, instead of __shfl_down, on warp scan
- Remove race conditions

* __shfl_up_sync with proper mask value for CUDA >= 9

* BlockScanInclusive for CUDA >= 9

* compatible_shfl_up for use in integral.hpp

* Use CLAHE in cudev

* Add tests for BlockScan

  * follow the implementation of Luv2RGBfloat in imgproc/src/color_lab.cpp
  * loosen threshold in cudaimgproc

Found via `codespell`

- 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

* cuda::cvtColor bug fix

Fixed bug in conversion formula between RGB space and LUV space.
Testing with opencv_test_cudaimgproc.exe, this commit reduces the number
of failed tests from 191 to 95. (96 more tests pass)

* Rename variables

CUDA9 build fixed, added detection (#9418)

* CUDA9 build fixed, added detection

* Replacing deprecated __shfl_xxx with __shfl_sync, fixing bogus CUDA9 warnings

  * stop using 'CUDA' prefix
  * add explanation

  * add feature of Fp16 on GPU (cudev)
  * add test
  * leave template function as unimplemented to raise error

add a note to use new cudev module as a replacement

it is generated by CUDA headers and we can't fix it