Update examples/tutorial

examples/tutorial/apc2016_obj3_json/info.yaml

-label_names:
-- _background_
-- shelf
-- highland_6539_self_stick_notes
-- mead_index_cards
-- kong_air_dog_squeakair_tennis_ball

examples/tutorial/apc2016_obj3_json/label_names.txt

 _background_
-shelf
 highland_6539_self_stick_notes
-mead_index_cards
 kong_air_dog_squeakair_tennis_ball
+mead_index_cards
+shelf

labelme/cli/json_to_dataset.py

@@ -6,7 +6,6 @@ import os.path as osp
 
 import imgviz
 import PIL.Image
-import yaml
 
 from labelme.logger import logger
 from labelme import utils
@@ -69,11 +68,6 @@ def main():
         for lbl_name in label_names:
             f.write(lbl_name + '\n')
 
-    logger.warning('info.yaml is being replaced by label_names.txt')
-    info = dict(label_names=label_names)
-    with open(osp.join(out_dir, 'info.yaml'), 'w') as f:
-        yaml.safe_dump(info, f, default_flow_style=False)
-
     logger.info('Saved to: {}'.format(out_dir))