OutputParams refactoring

[Yuriy Skalko]

> I never understood how it works, but I always assumed it was C++ for grown ups, jut without the lambda function mess. All I can say is that it works :)
> 
> JMarc

That's the most important thing, the rest are implementation details :)

Now I've found that Changer is just no-op variant of RefChanger. Their 
separation into different headers confused me.

Yuriy