Newinstance typehints

This pull request fixes problems with `newinstance()` when using base-classes with type hints.

E.g.
```php
class Base extends \lang\Object {
  public function fixture(array $a) { ... }
}

newinstance('name.of.Base', [], [
  'fixture' => function(array $a) { ... }
}];
```

This would lead to ***Fatal error: Declaration of Base·1::fixture() must be compatible with Base::fixture(array $a) ****