- Removed unused exception from PHP-docs.
- Fixed types not same as declared.
- Fixed issues with reg-ex and php-unit tests.
- Removed unnecessary type casting.
- Declared functions as static (better scoping + performance).
- Moved `\is_callable($callback) === false` as the execution costs less than previous in `Router.php`.
- Changed `ob_get_contents` to `ob_get_clean`.
- Added type hints to methods.