[WIP] [feature] UnusedUse - rewrite to use Tokens

UnusedUse - rewrite for use Tokens.
Work in progress

- [X] rewrite to use Tokens
- [X] fix #217
- [X] fix #317
- [X] fix #353
- [ ] set to run after `multiple_use` #480 (when merged!)
- [ ] squash commits
another typo. IT should be ``plit``, not ``splitted``. ``to split`` is an irregular verb