[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
Could you take a look at this test method: https://github.com/keradus/PHP-CS-Fixer/blob/unused-use/Symfony/CS/Tests/Fixer/UnusedUseStatementsFixerTest.php#L165 ?
Could you provide a testcase when this happened?

And, as you said, it is better not to remove unused use than to remove used one.
Especially when this won't happen when we add fixer for splitting multiple uses.