Transformer: explicitly indicate encoding (#313)
Transformer: explicitly indicate encoding (#313)

When using this on Windows, Python would complain about the UTF-8
encoding in the file:

```
Non-ASCII character '\\xc2' in file ./Transformer\\encoder.py on line 23, but no encoding declared; see http://python.org/dev/peps/pep-0263/ for details
```

Explicitly indicate the encoding in the file.
tensorflow/swift-models,tensorflow/swift-models,tensorflow/swift-models,tensorflow/swift-models