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

Conflicts:
	modules/calib3d/include/opencv2/calib3d/calib3d.hpp
	modules/core/include/opencv2/core/core.hpp
	modules/core/include/opencv2/core/cuda/limits.hpp
	modules/core/include/opencv2/core/internal.hpp
	modules/core/src/matrix.cpp
	modules/nonfree/test/test_features2d.cpp
	modules/ocl/include/opencv2/ocl/ocl.hpp
	modules/ocl/src/hog.cpp
	modules/ocl/test/test_haar.cpp
	modules/ocl/test/test_objdetect.cpp
	modules/ocl/test/test_pyrup.cpp
	modules/ts/src/precomp.hpp
	samples/ocl/facedetect.cpp
	samples/ocl/hog.cpp
	samples/ocl/pyrlk_optical_flow.cpp
	samples/ocl/surf_matcher.cpp