Release 0.7 - Add Torchscript capabilities
Author: thomwolf
Pull request: yes

Add Torchscript capabilities to all models.

Comments:
# [Codecov](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748?src=pr&el=h1) Report
> Merging [#748](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748?src=pr&el=desc) into [xlnet](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/commit/708877958a308a0f0e8fd199f8f327e4797f1583?src=pr&el=desc) will **increase** coverage by `0.21%`.
> The diff coverage is `96.06%`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748?src=pr&el=tree)

```diff
@@            Coverage Diff            @@
##           xlnet     #748      +/-   ##
=========================================
+ Coverage   71.5%   71.72%   +0.21%     
=========================================
  Files         35       35              
  Lines       5587     5633      +46     
=========================================
+ Hits        3995     4040      +45     
- Misses      1592     1593       +1
```


| [Impacted Files](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [...\_pretrained\_bert/tests/modeling\_transfo\_xl\_test.py](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748/diff?src=pr&el=tree#diff-cHl0b3JjaF9wcmV0cmFpbmVkX2JlcnQvdGVzdHMvbW9kZWxpbmdfdHJhbnNmb194bF90ZXN0LnB5) | `94.23% <100%> (ø)` | :arrow_up: |
| [pytorch\_pretrained\_bert/model\_utils.py](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748/diff?src=pr&el=tree#diff-cHl0b3JjaF9wcmV0cmFpbmVkX2JlcnQvbW9kZWxfdXRpbHMucHk=) | `92.61% <100%> (+0.04%)` | :arrow_up: |
| [pytorch\_pretrained\_bert/modeling.py](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748/diff?src=pr&el=tree#diff-cHl0b3JjaF9wcmV0cmFpbmVkX2JlcnQvbW9kZWxpbmcucHk=) | `87.55% <100%> (+0.47%)` | :arrow_up: |
| [pytorch\_pretrained\_bert/modeling\_openai.py](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748/diff?src=pr&el=tree#diff-cHl0b3JjaF9wcmV0cmFpbmVkX2JlcnQvbW9kZWxpbmdfb3BlbmFpLnB5) | `79.5% <100%> (+0.11%)` | :arrow_up: |
| [pytorch\_pretrained\_bert/modeling\_gpt2.py](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748/diff?src=pr&el=tree#diff-cHl0b3JjaF9wcmV0cmFpbmVkX2JlcnQvbW9kZWxpbmdfZ3B0Mi5weQ==) | `81.57% <100%> (+0.15%)` | :arrow_up: |
| [pytorch\_pretrained\_bert/modeling\_xlnet.py](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748/diff?src=pr&el=tree#diff-cHl0b3JjaF9wcmV0cmFpbmVkX2JlcnQvbW9kZWxpbmdfeGxuZXQucHk=) | `74.17% <83.33%> (+0.14%)` | :arrow_up: |
| [...torch\_pretrained\_bert/tests/model\_tests\_commons.py](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748/diff?src=pr&el=tree#diff-cHl0b3JjaF9wcmV0cmFpbmVkX2JlcnQvdGVzdHMvbW9kZWxfdGVzdHNfY29tbW9ucy5weQ==) | `97.08% <97.22%> (-0.01%)` | :arrow_down: |
| [pytorch\_pretrained\_bert/tokenization\_gpt2.py](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748/diff?src=pr&el=tree#diff-cHl0b3JjaF9wcmV0cmFpbmVkX2JlcnQvdG9rZW5pemF0aW9uX2dwdDIucHk=) | `82.44% <0%> (-1.07%)` | :arrow_down: |

------

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> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748?src=pr&el=footer). Last update [7088779...b43b130](https://codecov.io/gh/huggingface/pytorch-pretrained-BERT/pull/748?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).