Remove nb_cols from dataset file

Closes #67 (closed)

dan/manager/dataset.py

@@ -17,7 +17,7 @@ from dan.transforms import apply_data_augmentation
 class DatasetManager:
     def __init__(self, params):
         self.params = params
-        self.dataset_class = params["dataset_class"]
+        self.dataset_class = None
         self.img_padding_value = params["config"]["padding_value"]
 
         self.my_collate_function = None