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

Conflicts:
	CMakeLists.txt
	modules/calib3d/src/calibration.cpp
	modules/ocl/src/cl_programcache.cpp
	modules/ocl/src/filtering.cpp
	modules/ocl/src/imgproc.cpp
	samples/ocl/adaptive_bilateral_filter.cpp
	samples/ocl/bgfg_segm.cpp
	samples/ocl/clahe.cpp
	samples/ocl/facedetect.cpp
	samples/ocl/pyrlk_optical_flow.cpp
	samples/ocl/squares.cpp
	samples/ocl/surf_matcher.cpp
	samples/ocl/tvl1_optical_flow.cpp

samples/ocl/hog.cpp

@@ -73,6 +73,14 @@ int main(int argc, char** argv)
         "{ l |larger_win| false          | use 64x128 window}"
         "{ o |  output  |                | specify output path when input is images}";
     CommandLineParser cmd(argc, argv, keys);
+    if (cmd.has("help"))
+    {
+        cout << "Usage : hog [options]" << endl;
+        cout << "Available options:" << endl;
+        cmd.printMessage();
+        return EXIT_SUCCESS;
+    }
+
     App app(cmd);
     try
     {
@@ -90,7 +98,7 @@ int main(int argc, char** argv)
     {
         return cout << "unknown exception" << endl, 1;
     }
-    return 0;
+    return EXIT_SUCCESS;
 }
 
 App::App(CommandLineParser& cmd)