Goals

- Shared between client and server (and thus not in avya-common)
- Write a fully immutable version of Ref (should I use immutable.js?)
- Write a consistent version of SchemaTraversal. And RefTraversal?
- Use flow on all files. Export types
- Test as much as possible so that I can work on a solid foundation

Modules

- Ref. Use Immutable.js so that we don't need a RefBuilder
- SchemaTraversal. Same as old one but with a consistent interface
- RefTraversal. Traverses a ref through a schema.
- Ref normalization/denormalization? Possibly