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

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

Conflicts:
	apps/CMakeLists.txt
	modules/contrib/CMakeLists.txt
	modules/core/include/opencv2/core/version.hpp
	modules/imgproc/include/opencv2/imgproc/imgproc.hpp
	modules/java/generator/gen_java.py
	modules/ocl/include/opencv2/ocl/ocl.hpp
	modules/ocl/src/cl_runtime/cl_runtime.cpp
	modules/ocl/src/columnsum.cpp
	modules/ocl/src/filtering.cpp
	modules/ocl/src/imgproc.cpp
	modules/ocl/test/main.cpp
	modules/ocl/test/test_color.cpp
	modules/ocl/test/test_imgproc.cpp
	samples/gpu/CMakeLists.txt