* setTo_#10507

* setTo_Nan_10507

* setTo: update check / test for NaNs

* core:ppc Fix java CoreTest/testMahalanobis

* core:ppc Fix warning unused variable on clang

should hide unnecessary 'info' messages

If this seems too wordy, take into account a new user who tries to find out extent of FP16 support in OpenCV.

fixes handling of empty matrices in some functions (#11634)

* a part of PR #11416 by Yuki Takehara

* moved the empty mat check in Mat::copyTo()

* fixed some test failures

- cvdef.h + cvRound (double only)
- highgui_c.h

resolves #11511

* make sure that the matrix with more than INT_MAX elements is marked as non-continuous, and thus all the pixel-wise functions process it correctly (i.e. row-by-row, not as a single row, where integer overflow may occur when computing the total number of elements)

'0' is specific case (make no sence as a standalone operation),
but it can be useful in template-based programming.

reverts commit: a58c9d4d

  * remove meaningless tests

* add v_float64x2 support to v_rotate_*
* treat float vector in v_check_any, vec_any_lt as int vector
* add test case for v_rotate_left

* Resolves 6125

* Fix test code

* Delete unnecessary code

to avoid accessing of 'p[-1]' (static code analysers dislike this)

for cv::Mat with type=16UC3 and width < 16

std::exception_ptr requires enabled C++11 mode

for cv::Mat with width < 16

improved performance of v_load_deinterleave(8uC3) & v_store_interleave(8uC3) intrinsics when using SSSE3 instructions.

To dump contents of the last OpenCV error

v_select 'mask' is restricted to these values only: 0 or ~0 (0xff/0xffff/etc)
mask in accuracy test is updated.

* 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

* Fix CV_Asserts with negation of strings

{!"string"} causes some compilers to throw a warning.

The value of the string is not that important -- it's only for printing
the assertion message.

Replace these calls with:

  CV_Error(Error::StsError, "string")

to suppress the warning.

* remove unnecessary 'break' after CV_Error()

Error messages are available via exceptions