* - headers in "infer/" and "infer/ie/" folders are included into gapi_ext_hdrs;
+ because of that a few #includes are required in the headers
- HAVE_INF_ENGINE flag check in headers "infer/ie.hpp" and "infer/ie/util.hpp" is deleted
* - the "ie/util.hpp" header is a private header now as it's used for tests; it's been moved to the scr directory to the place next to the implementation file "ie/giebackend.cpp"
- the path to this header in files "ie/giebackend.cpp" and "test/infer/gapi_infer_ie_test.cpp" is updated
- As it's private header now and explicitly depends on IE, the "HAVE_INF_ENGINE" flag check is returned
* Support GArray as input in fluid kernels
* Create tests on GArray input in fluid
* Some fixes to fully support GArray
* Refactor code and change the kernel according to review
* Add histogram calculation as a G-API kernel
Add assert that input GArgs in fluid contain at least one GMat
* Convert lkpyramid from SSE SIMD to HAL - 90% faster on Power (VSX).
* Replace stores with reduce_sum. Rework to handle endianess correctly.
* Fix compiler warnings by casting values explicitly to shorts
* Switch to CV_SIMD128 compiler definition. Unroll loop to 8 elements since we've already loaded the data.
Detected by clang trunk:
```
opencv/modules/core/src/ocl.cpp:4337:37: warning: object backing the pointer will be destroyed at the end of the full-expression [-Wdangling]
CV_OCL_CHECK_RESULT(retval, cv::format("clCreateBuffer(capacity=%lld) => %p", (long long int)entry.capacity_, (void*)entry.clBuffer_).c_str());
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
opencv/modules/core/src/ocl.cpp:193:42: note: expanded from macro 'CV_OCL_CHECK_RESULT'
if (0) { const char* msg_ = (msg); CV_UNUSED(msg_); /* ensure const char* type (cv::String without c_str()) */ } \
```
because `cv::format` yields a temporary std::string, and thus `msg_` points to a destroyed buffer.
* Fix the detection of XIMEA on Windows (when it has been installed by another user with administrative privileges, for example).
* Change the flow: we first try HKEY_CURRENT_USER key and, if empty, then try HKEY_LOCAL_MACHINE
