proposed fix for issue #38

Hi,

I think I have a useful contribution to share, however, I am fairly new to Git, Mac, iOS, Objective C, this library, and well pretty anything that would inspire a sense of confidence in this change.  As such, this request should probably get a thorough review.  For example, the change only addresses implicit arrays when mapped to a dictionary, but I didn't see any obvious way to handle "simple" values, e.g. an implicit array of a single string.  Did I overlook something?  Is that even a valid use case?  Let me know how else I can help, and thanks for making this lib!

-Nate