Use KDTREE flann algorithm by default

Former-commit-id: 58f41aa498

opendm/osfm.py

@@ -135,6 +135,7 @@ class OSFMContext:
             # create config file for OpenSfM
             config = [
                 "use_exif_size: no",
+                "flann_algorithm": "KDTREE", # more stable, faster than KMEANS
                 "feature_process_size: %s" % args.resize_to,
                 "feature_min_frames: %s" % args.min_num_features,
                 "processes: %s" % args.max_concurrency,