Linting

[iamdefinitelyahuman]

• Added additional annotations, mypy checks now passing across entire project.
• Increased black max line length to 100, replaced flake8 lint checks with black.
• Applied isort formatting, added to lint build
• Separated slower tests into their own builds (added --evm-tests and --mix-tests flags)

Closes #210

[ghost]

Thanks for getting all the typing imports in alphabetical order. I meant to go back and do that. Does black or any other tool do that automatically or did you adjust manually?

[iamdefinitelyahuman]

@crawfordleeds it's isort.. wonderful tool :)