cv::format declaration in default headers
CLAHE
added the first T-API example - CamShift tracking
implemented OpenCL version of cv::convertScaleAbs
added OpenCL version of cv::scaleAdd
converted CPU-based example to T-API (Mat 2 UMat, etc)
eliminate MINGW pragma warning
fix
Merge pull request #2092 from alalek:fix_mingw_warn
fixed bug #3341
[emscripten] Do not link to system libraries

This is not meaningful when compiling to javascript, and causes warning
at linking stage.
SSE2 optimization of cv::remap doesn't work with big images
Merge pull request #2089 from ilya-lavrenov:tapi_examples
Merge pull request #2085 from severin-lemaignan:emscripten
Merge pull request #2086 from ilya-lavrenov:mul_fix
Fixed MinGW build by declaring the minimal required Windows version.

Also deleted miscellaneous remaining multimon cruft.
Deleted #include <winuser.h>, because <windows.h> includes it
already.

This should have a nice side effect of preventing us from
accidentally using any Windows API that's too new.
Merge pull request #2087 from ilya-lavrenov:remap_sse2_cond
fixed umat access
added OpenCL version of cv::patchNaNs
Merge pull request #2091 from ilya-lavrenov:tapi_convertScaleAbs