First occurence of 4-directional version of SGBM.

Even without any tests.
Next step is parallelising it.

modules/calib3d/include/opencv2/calib3d.hpp

@@ -1809,7 +1809,8 @@ public:
     {
         MODE_SGBM = 0,
         MODE_HH   = 1,
-        MODE_SGBM_3WAY = 2
+        MODE_SGBM_3WAY = 2,
+        MODE_HH4  = 1
     };
 
     CV_WRAP virtual int getPreFilterCap() const = 0;