'async' is a reserved word in Python >= 3.7

[cclauss]

Same problem and recommended fix as CSAILVision/semantic-segmentation-pytorch#125

flake8 testing of https://github.com/CSAILVision/unifiedparsing on Python 3.7.1

$ flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics

./lib/nn/parallel/data_parallel.py:16:31: E999 SyntaxError: invalid syntax
        v = obj.cuda(dev, async=True)
                              ^
./models/models.py:163:27: F821 undefined name 'ResnetDilated'
            net_encoder = ResnetDilated(orig_resnet,
                          ^
./models/models.py:168:27: F821 undefined name 'ResnetDilated'
            net_encoder = ResnetDilated(orig_resnet,
                          ^
1     E999 SyntaxError: invalid syntax
2     F821 undefined name 'ResnetDilated'
3

[drmeerkat]

the same problem. Change to non_blocking works ! Thanks !

[cclauss]

@hangzhaomit Your review please.