Multiple Http headers fix

Hi

I found that by calling:

```$response->setStatusCode(200, 'OK');
   $response->setStatusCode('404', 'NotFound');
   $response->setStatusCode('409', 'Conflict');```

Phalcon\Response will ```setRaw``` 3 HTTP headers (which are invalid response). Code here:
https://github.com/phalcon/cphalcon/blob/1.3.0/ext/http/response.c#L250

There's some problem with that code - could somebody please give me a hand?

Thanks in advance,

Kamil