Add more tests

[atljeremy]

We need more tests around nested object mapping

Ex.

let userJSON: [String: AnyObject] = [
    "id": 12345,
    "name": "John Appleseed",
    "contact_info": [
        "email": "test@test.com",
        "phone": 2223334444,
        "address": "123 Main St",
        "city": "Atlanta",
        "state": "GA",
        "zip": "12345"
    ]
]

In the example JSON object above, we'd need a model for User and ContactInfo and would need the mapping of each respective object to happen seamlessly. This is all working, but we need to add more tests around this.