Add http socket to the module sockets array and allow the framework to cleanup

Two small changes:

* Just add the http socket to the module sockets array with ```add_socket``` and allow the framework to ```cleanup``` instead of calling it from the own module. Shouldn't be a problem, but just to avoid an early cleanup.

* ```send_image_request``` and ```send_video_request``` were returning ```http```. I'm guessing they were intended to return ```res```. Do you mind to confirm? I cannot test! Please, feel free to verify, accept or decline any change and ready to go!