* Issue 11242 intrinsics v_extract, v_rotate improvement, branch 3.4, without C++11 (remove type restrictions for SSE2, use PALIGNR on SSSE3, compile to no-op when imm is 0 or nlanes).
* fix whitespace
* Fix#11242 (NEON intrinsics v_rotate...) branch 3.4
Separate macro expansion OPENCV_HAL_IMPL_NEON_SHIFT_OP for bitwise shifts for integers, from macro expansion OPENCV_HAL_IMPL_NEON_ROTATE for lane rotations. Bitwise shifts do not apply to floats, but lane-rotations can apply to both.
* fix whitespace
* Fix#11242 compile error (VSX intrinsics v_rotate(a)) branch 3.4 no-c++11
* use universal intrinsic instead of raw intrinsic
* add 2 channels de-interleave on x86 platform
* add v_int32x4 version of v_muladd
* add accumulate version of v_dotprod based on the commit from seiko2plus on bf1852d
* remove some verify check in performance test
* avoid the out of boundary access and keep the performance
* loosen some test threshold mainly for integer types
* use relative error for floating points result
* avoid division by zero by following the comment
* fix the indentation
* Make <array> #ifdef true for MSVC
I think MSVC had `std::array` for quite a while (possibly going back as far as VS 2012, but it's definitely there in 2015 and 2017. So I think `_MSC_VER` `1900` is a safe bet. Probably `1800` and maybe even `1700` could work as well but I can't test that locally.
* fix test
- 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 raw SSE2/NEON implementation from convert.cpp
* remove raw implementation from Cvt_SIMD
* remove raw implementation from cvtScale_SIMD
* remove raw implementation from cvtScaleAbs_SIMD
* remove duplicated implementation cvt_<float, short>
* remove duplicated implementation cvtScale_<short, short, float>
* add "from double" version of Cvt_SIMD
* modify the condition of test ConvertScaleAbs
* Update convert.cpp
fixed crash in cvtScaleAbs(8s=>8u)
* fixed compile error on Win32
* fixed several test failures because of accuracy loss in cvtScale(int=>int)
* fixed NEON implementation of v_cvt_f64(int=>double) intrinsic
* another attempt to fix test failures
* keep trying to fix the test failures and just introduced compile warnings
* fixed one remaining test (subtractScalar)
