[Docs] Add modelzoo statistics and polish docs (#201)

* add model stastics

* add model stastics and polish docs

* add model stastics and polish docs

* fix

* chmod +x stat.py

tests/test_forward.py

@@ -37,8 +37,8 @@ def _get_config_module(fname):
 def _get_detector_cfg(fname):
     """Grab configs necessary to create a detector.
 
-    These are deep copied to allow for safe modification of parameters
-    without influencing other tests.
+    These are deep copied to allow for safe modification of parameters without
+    influencing other tests.
     """
     import mmcv
     config = _get_config_module(fname)

tools/fuse_conv_bn.py

 import argparse
 import torch
-import torch.nn as nn
 from mmcv.runner import save_checkpoint
+from torch import nn as nn
 
 from mmdet.apis import init_detector