Pass captured regex values to route handler defined as functions.

This update allows `$regex_matches` to be passed to handler methods the same way they are called when using a class handler.

For example:
```php
'/route/([page1/page2/page3])+)' => function ($page) {
 switch($page) {
  case 'page1':
  break;
  case 'page2':
  break;
 }
},
'/another/:number' => function ($number) { ... }
```