Add default parameters for SGBM::create

Added default parameters for minDisparity, numDisparities and blockSize. This fixes a bug where SGBM::load would not compile.

modules/calib3d/include/opencv2/calib3d.hpp

@@ -1917,7 +1917,7 @@ public:
     set StereoSGBM::numDisparities at minimum. The second constructor enables you to set each parameter
     to a custom value.
      */
-    CV_WRAP static Ptr<StereoSGBM> create(int minDisparity, int numDisparities, int blockSize,
+    CV_WRAP static Ptr<StereoSGBM> create(int minDisparity = 0, int numDisparities = 16, int blockSize = 3,
                                           int P1 = 0, int P2 = 0, int disp12MaxDiff = 0,
                                           int preFilterCap = 0, int uniquenessRatio = 0,
                                           int speckleWindowSize = 0, int speckleRange = 0,