change default logger to dedicated one (#1064)

Fix test


Fix format

Update pytorch_lightning/__init__.py
Separate imports

pl_examples/basic_examples/lightning_module_template.py

@@ -1,7 +1,6 @@
 """
 Example template for defining a system
 """
-import logging as log
 import os
 from argparse import ArgumentParser
 from collections import OrderedDict
@@ -14,6 +13,7 @@ from torch import optim
 from torch.utils.data import DataLoader
 from torchvision.datasets import MNIST
 
+from pytorch_lightning import _logger as log
 from pytorch_lightning.core import LightningModule