- `autopep8 -aa` for general cleanup;
- Changed order of imports, they should be ordered into 3 groups:
1. standard library imports;
2. 3rd party packages;
3. project imports.
- I commented various imports that were reported as unused by my IDE.
If everything goes fine we can consider to delete them;
- The Apache license disclaimers are now comments since triple-quotes
should be used only for docstrings;
- Fix - `utils.centerWindowOnParent` did not resolve, changed to
`centerWindowOnParent`
