Provide projo serializer for Jackson ObjectMapper

[raner]

Jackson is a very commonly used JSON serializer/deserializer, and it would be great if a module could be added that allows Jackson to create and parse Projo objects.

See https://github.com/FasterXML/jackson-docs/wiki/JacksonHowToCustomSerializers

[raner]

The initial implementation of Jackson serialization and deserialization support was completed with commit 94bb6d1.