Python 3 support and general fixes/refactor

[avanbrunt-cb]

Pull request checklist

Please check if your PR fulfills the following requirements:

• [x] Docs have been reviewed and added / updated if needed (for bug fixes / features)
• [x] Tests have been added that prove the fix is effective or that the feature works.
• [x] New and existing tests pass locally with the changes.
• [x] Code follows the style guidelines of this project (PEP8, clean code).
• [x] Linter has passed locally and any fixes were made for failures.
• [x] A self-review of the code has been done.

Pull request type

Please check the type of change your PR introduces:

• [x] Bugfix
• [x] Feature
• [x] Code style update (formatting, renaming)
• [x] Refactoring (no functional changes, no api changes)
• [x] Build related changes
• [x] Documentation content changes (not tied to bugs/features)
• [ ] Other (please describe):

What is the ticket or issue number?

N/A

Pull Request Description

Refactored the entire code base and rewrote a portion of the leef parser Fixed all tests so they pass

Does this introduce a breaking change?

• [x] Yes
• [ ] No

How Has This Been Tested?

Manual and unit tests