Merge remote-tracking branch 'origin/2.4' into merge-2.4

Conflicts:
	.gitignore
	modules/contrib/src/detection_based_tracker.cpp
	modules/core/include/opencv2/core/core.hpp
	modules/core/include/opencv2/core/internal.hpp
	modules/core/src/gpumat.cpp
	modules/core/src/opengl.cpp
	modules/gpu/src/cuda/safe_call.hpp
	modules/highgui/src/cap.cpp
	modules/imgproc/include/opencv2/imgproc/imgproc.hpp
	modules/ocl/doc/image_processing.rst
	modules/ocl/include/opencv2/ocl/ocl.hpp
	modules/ocl/perf/perf_haar.cpp
	modules/ocl/src/haar.cpp
	modules/ocl/src/imgproc.cpp
	modules/ocl/src/kmeans.cpp
	modules/ocl/src/svm.cpp
	modules/ocl/test/test_objdetect.cpp
	samples/ocl/adaptive_bilateral_filter.cpp

modules/core/src/copy.cpp

@@ -485,6 +485,7 @@ void repeat(InputArray _src, int ny, int nx, OutputArray _dst)
 {
     Mat src = _src.getMat();
     CV_Assert( src.dims <= 2 );
+    CV_Assert( ny > 0 && nx > 0 );
 
     _dst.create(src.rows*ny, src.cols*nx, src.type());
     Mat dst = _dst.getMat();