Add body property to JSONAPIDocument protocol

0.4.1

Add body variable to JSONAPIDocument protocol

Create protocol over JSONAPIDocument

Breaking change that creates a JSONAPIDocument protocol and renames the existing struct to just Document.

TestLib

A new target called JSONAPITestLib adds features aimed at testing an integration with JSONAPI.

A change to the structure of a JSONAPIDocument Body makes it easier to pass a success body around.

Lots of new encoding, decoding, and testing

The library gains support for a lot more decoding, encoding, and initialization. All of it gets better unit test coverage.

First pre-release

The library does not support the entire JSON API spec and it doesn't allow initialization of JSONAPIDocument except for by decoding data, but nevertheless it has reached a minimum threshold of usability and test coverage that I think is worth versioning.

There will likely be breaking changes ahead.