Returns empty array if Blockchain says there aren't any unspent transactions

Blockchain just outputs "No free outputs to spend" when the address hasn't received any transactions. JSON parsing fails, and so it falls through, and returns nil. It really should otherwise return an empty array, which I've set it up to do. In the context of this error, code 3840 means a JSON parsing error, which means Blockchain is returning "No free outputs to spend". As for errorOut, because we know that an error didn't *really* happen, it's just the way Blockchain communicates an empty list, we errorOut will remain nil.