Add circle CI for building PyTorch 1.1/1.2/1.3

[Borda]

Adding one more CI to have built with all major PyTorch releases. Adding this to existing Travis will make each build too long since Travis and CircleCI will run in parallel...

Before submitting

• Was this discussed/approved via a Github issue? (no need for typos, doc improvements)
• Did you read the contributor guideline?
• Did you make sure to update the docs?
• Did you write any new necessary tests?

What does this PR do?

Fixes #462. Reaction to #491.

PR review

Anyone in the community is free to review the PR once the tests have passed.
If we didn't discuss your PR in Github issues there's a high chance it will not be merged.

[Borda]

well, it seems that the CricleCI is so slow... :-(

[Borda]

also tests/test_gpu_models.py::test_cpu_slurm_save_load Too long with no output (exceeded 10m0s) so it should be revisited...