Parameterized Response Type (RestResponse<>)

This is something that I think many people want, and I needed for a project I am working on.  It maintains backwards compatibility.  I'd suspect in R2.0 it would be worth stripping this if you plan to make Response parameterized (as I read in the Docs pages).

You can see very basic usage support in the tests.
What do you have in mind here?  I'm still a little new to some of the nuances of Java, so I am not sure of the best approach to this.  Obviously I'd need to make `Response` not final, but from there - would you pass null as `TypedInput` and have another field in the `RestResponse` class with a different getter?