change default logger to dedicated one (#1064)

Fix test


Fix format

Update pytorch_lightning/__init__.py
Separate imports

pytorch_lightning/callbacks/early_stopping.py

@@ -5,12 +5,12 @@ Stop training when a monitored quantity has stopped improving.
 
 """
 
-import logging as log
 import warnings
 
 import numpy as np
 
 from .base import Callback
+from pytorch_lightning import _logger as log
 
 
 class EarlyStopping(Callback):

pytorch_lightning/callbacks/model_checkpoint.py

@@ -5,7 +5,6 @@ Model Checkpointing
 Automatically save model checkpoints during training.
 """
 
-import logging as log
 import os
 import shutil
 import warnings
@@ -14,6 +13,7 @@ import re
 import numpy as np
 
 from pytorch_lightning.callbacks.base import Callback
+from pytorch_lightning import _logger as log
 
 
 class ModelCheckpoint(Callback):