dramatic speedup of SVM::predict in the case of linear SVM

modules/ml/include/opencv2/ml/ml.hpp

@@ -534,6 +534,8 @@ protected:
     virtual void write_params( CvFileStorage* fs ) const;
     virtual void read_params( CvFileStorage* fs, CvFileNode* node );
 
+    void optimize_linear_svm();
+
     CvSVMParams params;
     CvMat* class_labels;
     int var_all;