resolveReferences to handle object-value tokens

[jorenbroekema]

resolveReferences currently only works on string values, but object-value tokens can also contain reference so they should be handled as well.

Right now because Style Dictionary uses a object traversal wrapper around resolveReferences (resolveObject, private API), this isn't a problem usually, but it is a problem if you're aiming to use the standalone resolveReferences utility on object-values