Add table of contents

• Added a table of contents
• Updated the numbering of the headlines
• Minor change in the script data_utils.py in directory utils to use the new style for string formatting

closes #1

utils/data_utils.py

@@ -49,7 +49,7 @@ class DataValidator:
             if not os.path.exists(data_dir):
                 data_dir = os.path.join(os.path.abspath('../../datasets'))
 
-            print('Using %s as the data directory.' % data_dir)
+            print('Using {} as the data directory.'.format(data_dir))
 
         # Check if the directory exists
         assert os.path.exists(data_dir), \