Code migrated to python > 3.7

[gattjoe]

Almost all of the code has been rewritten to be compatible with > Python 3.7. Additionally, I added some typing hints to the functions throughout.

Please note: I have two breaking changes that I need more time to fix: the ability to POST data and the ability to run this through a proxy. I can work on these tomorrow, as well as refactoring some of the code to be more modular. I think my todo's are:

1. re-add the ability to POST data
2. re-add the ability to use a proxy
3. Add some automated tests to make testing quicker
4. Update setup.py so that you can update the version in pip
5. Others?