Adds raw_response config option

Defaults to fault. This allows someone to get a Hash representation of the JSON response body rather than a custom Ruby object.
Adds a preliminary Quote object
Adds a timeify utility method

Apparently not all time fields have a time in them, e.g., `pickup_eta` and `dropoff_eta` can be `nil`. I've moved the string to `DateTime` object conversion into a `timeify` method in the `Utils` module. If no string is passed, I allow `nil` as a value. I'll look into whether a default `DateTime` object makes more sense here in the future.
Adds a preliminary Delivery object