Small fixes for SimpleFlow algorithm

+ Fixed warnings
+ Add new function calcOpticalFlow with smaller number of arguments
+ Add asserts to algorithm and remove 'exit(1)'

modules/video/include/opencv2/video/tracking.hpp

@@ -328,6 +328,13 @@ CV_EXPORTS_W Mat estimateRigidTransform( InputArray src, InputArray dst,
                                          bool fullAffine);
   
 //! computes dense optical flow using Simple Flow algorithm
+CV_EXPORTS_W void calcOpticalFlowSF(Mat& from, 
+                                    Mat& to,
+                                    Mat& flow,
+                                    int layers,
+                                    int averaging_block_size, 
+                                    int max_flow);
+
 CV_EXPORTS_W void calcOpticalFlowSF(Mat& from, 
                                     Mat& to,
                                     Mat& flow,