Access to OpenAPI string formats #197

OpenAPI allows string fields in responses to indicate what type of data they contain using the format property.

Currently this client doesn't expose access to this property in any way, so consumers can't do programmatic data type conversion on these properties.

It would make sense and be very useful to expose this property somehow, possibly through a deserializer or transformer function specifically for strings with formats.

This would be particularly useful for date/time formats, but would also open up flexibility to support any data format the consumer would want to support.