Build tutorial codes together with other samples

These codes should be included into regular builds.

samples/cpp/tutorial_code/Histograms_Matching/calcHist_Demo.cpp

@@ -15,7 +15,7 @@ using namespace cv;
 /**
  * @function main
  */
-int main( int argc, char** argv )
+int main( int, char** argv )
 {
   Mat src, dst;