Fourth release
New:
- 3-4 times speed-up in fp16 thanks to NVIDIA's work on apex
- SWAG (multiple-choice) model added + example fine-tuning on SWAG
- bump up to PyTorch 1.0
- backward compatibility to python 3.5
- load fine-tuned model with `from_pretrained`
- add examples on how to save and load fine-tuned models