Implement a helper for Iterator[Box[T]] => Box[List[T]]

So, I've run into cases before where I have a for comprehension I need to execute that returns an `Iterator[Box[T]]`, but the return type of the method I'm building is `Box[T]`. When I'm in this situation, the following is true:

* I want a `Full[List[T]]` in the event that all Boxes are full.
* I want a `ParamFailure[List[Box[T]]]` in the event that one or more `Failure` existed in the `Iterator[Box[T]]`.