PyTorch version to screen and cleanup (#1325)

* Create flatten_recursive() helper function

* cleanup

* print torch version

models/yolo.py

@@ -1,11 +1,10 @@
 import argparse
 import logging
+import math
 import sys
 from copy import deepcopy
 from pathlib import Path
 
-import math
-
 sys.path.append('./')  # to run '$ python *.py' files in subdirectories
 logger = logging.getLogger(__name__)
 
@@ -74,7 +73,7 @@ class Model(nn.Module):
 
         # Define model
         if nc and nc != self.yaml['nc']:
-            print('Overriding model.yaml nc=%g with nc=%g' % (self.yaml['nc'], nc))
+            logger.info('Overriding model.yaml nc=%g with nc=%g' % (self.yaml['nc'], nc))
             self.yaml['nc'] = nc  # override yaml value
         self.model, self.save = parse_model(deepcopy(self.yaml), ch=[ch])  # model, savelist, ch_out
         # print([x.shape for x in self.forward(torch.zeros(1, ch, 64, 64))])
@@ -93,7 +92,7 @@ class Model(nn.Module):
         # Init weights, biases
         initialize_weights(self)
         self.info()
-        print('')
+        logger.info('')
 
     def forward(self, x, augment=False, profile=False):
         if augment: