Fix conflict between translator service in ZF2 and skeleton app

[weierophinney]

This fixes a conflict raised by #4391 and reported in zendframework/ZendSkeletonApplication#184 -- basically, the skeleton application was defining a "translator" factory already, which meant that with the changes on ZF2, we were creating a conflict for anybody upgrading their existing app to the latest master.

What this PR does is create a new "MvcTranslator" service, using the MVC's translator factory. This ensures the original translator factory continues to work, while allowing validators to work in a turn-key fashion.

[prolic]

Well, I don't like the "Mvc"-prefix, because we don't have these on any other service defined in zf2.
Unfortunatly, I don't see another solution, too.

So, good to merge :-(

[danizord]

I think the problem is in SkeletonApplication, not here.
It is a good practice to register our application services named by FQCN or prefixed by vendor name, it avoids conflicts with these services defined within the Framework.

[prolic]

@danizord agree, but....
The Skeleton Application is also released, BC breaks in another repo doesn't solve this point.

[weierophinney]

@danizord as @prolic notes, if we don't make this change, anybody who used the skeleton app prior to 2.2 and who then updates to 2.2 will have a broken application. This is really the best way to go.

Regarding why I'm using the name "MvcTranslator" -- it's because it's an MVC-specific factory that uses a version of the Translator that implements interfaces from multiple components. You can see a similar implementation in the aura.framework package. We could introduce a "framework" or "integration" component, but, for all intents and purposes, our MVC component is already that component.

[danizord]

@weierophinney Got it. The "Zend\Integration" does not sound like a bad idea for the next release.

[padraic]

Again, looks fine here.