Allow to get response without headers

[benfavre]

Could you please wrap theses with an if statement so I can wrap the application class to emulate PSR-7
Right now I have no easy way of only getting the reponse back and handling it as i please.

https://github.com/phalcon/cphalcon/blob/master/phalcon/mvc/application.zep#L394
https://github.com/phalcon/cphalcon/blob/master/phalcon/mvc/application.zep#L395

[stamster]

Indeed this might be useful (actually required) to integrate ReactPHP with Phalcon. So Phalcon would not send raw HTTP headers nor body but rather return entire Response object instead.

[sergeyklay]

Implemented in the 3.3.x branch. Thank you for contributing.