Issue: #73 - GenericHTTP actor.

* Unify mock_tornado() and tornado_value() helper functions during testing.
No, it just returns as False. Exceptions are only raised when the actor can't perform what is asked of it. If someone requests a page that does not exist, and `404` is returned it's not a python exception, it's just a failure.

Raising exception here, would be equivalent to your browser crashing when you make a typo in the URL