Sdc-cryptography

- Release to facilitate a Travis Pypi deployment.

- Update packages to address vulnerabilities in cryptography package.
- Bumped major version as this package is widely used in production applications

- Update pyyaml due to CVE-2017-18342
- Python 3.4 is no longer supported; the minimum supported Python version is 3.5

- Create public key IDs more consistently
- Use pipenv and update unit test coverage
- Unpin packages to allow for easier depedency upgrades

- Update cryptography and jwcrypto due to CVE-2018-10903

- Update pyyaml to 3.13 because of CVE-2017-18342