Add Java and Python code for AKAZE local features matching tutorial. Fix incorrect uses of Mat.mul() in Java code.

Uniform Lowe's ratio test in the code.

samples/python/tutorial_code/features2D/feature_homography/SURF_FLANN_matching_homography_Demo.py

@@ -29,7 +29,7 @@ knn_matches = matcher.knnMatch(descriptors_obj, descriptors_scene, 2)
 ratio_thresh = 0.75
 good_matches = []
 for m,n in knn_matches:
-    if m.distance / n.distance <= ratio_thresh:
+    if m.distance < ratio_thresh * n.distance:
         good_matches.append(m)
 
 #-- Draw matches