[feature] UnusedUse - rewrite to use Tokens and fix issues #217, #317, #353

UnusedUse - rewrite for use Tokens.
Work in progress

- [X] rewrite to use Tokens
- [X] fix #217
- [X] fix #317
- [X] fix #353
- [X] set to run after `multiple_use` #480 (when merged!)
- [X] squash commits
@stof But you know what? We can at least make it cross-OS ;)
and... done!