Upgrade needed for pytorch 0.4+

[fac2003]

The current master won't work with pytorch 0.4: isinstance cannot test for TensorBase anymore and there are other issues discussed in the migration guide.
I have migrated torchfold in this fork: https://github.com/CampagneLaboratory/torchfold/tree/pytorch_0.4.1
Note that the branch also partly addresses an issue with incorrect logic in the training loop of the example, so let me know if you want a PR.

[ilblackdragon]

@fac2003 Sorry for late reply. Feel free to send the PR to upgrade to v1.0 if that's still interesting.
Thanks!

[fac2003]

I will need to use torchfold in the very near future with 1.0, and can send a PR when I have tested the code with pytorch 1.0. Note that the upgrade to 0.4 should cover most of the API changes. 0.4 and 1.0rc1 are quite similar in term of API.

[gameking157]

update to 1.0 please