The cats version

Complete rewrite of the API, based on cats. The core library now really focuses on creating and managing patches only. In particular, it doesn't take care of (de)serializing Json anymore.

The different diff algorithms are managed by providing an instance of Diff, and patches to be apply need to have an instance of Patch.

To add support for your Json AST, you simply need to provide an instance of Jsony, which is way smaller than the previous way of doing it.