Autoflake the repository.

[benjaminrwilson]

Use autoflake to clean up the repository.

For reference, the following command was used from the root directory:

autoflake --expand-star-imports --remove-all-unused-imports --remove-duplicate-keys --ignore-init-module-imports --remove-unused-variables --in-place --recursive .

[benjaminrwilson]

@johnwlambert, let me know if you have any other concerns.

[johnwlambert]

Hi Ben, left a few comments. Thanks for all the updates