Make Collection load values when adding them into it

[blanquer]

If you have say, a Collection.of(Attributor::Hash) ... you can easily initialize an instance by calling the .load method. That will propertly load/coerce/convert the elements to the appropriate type (i.e. Attributor::Hash in this case).

However, if you add an element to it (i.e. using <<) we'll blindly store the instance you pass without loading it. Same applies for any native Array methods that set/change elements.

I think we need to override those "settable/updatable" functions and force a load first.

Otherwise, it might look like you're setting the right things (i.e., a ruby Hash, instead of an Attributor::Hash) as one of the elements...but which will then fail validation. Same for Strings vs. Symbols...etc