Set component when it is different from the requested one

I started the issue [here](https://github.com/fuelphp/foundation/issues/12)

It attempts to solve the current component problem outlined there.

Not sure if it is the best possible solution, but shows how I imagine it.

@WanWizard please confirm that I am correct and the component in a request should be the component resolved by the router and not the one the request came from (usually the root component).