JSONSchemaFactory does not support $ref

[serhalp]

Given this JSON Schema:

  $schema: "http://json-schema.org/schema#"

  definitions:
    order:
      type: 'object'
      required: ['status']
      properties:
        status:
          type: 'boolean'

  type: 'object'
  required: ['order']
  properties:
        updatedOrder:
          $ref: "#/definitions/order"

The expected behavior of unionized.JSONSchemaFactory instantiated with this schema is the same as that instantiated with the following schema:

  $schema: "http://json-schema.org/schema#"

  type: 'object'
  required: ['order']
  properties:
        updatedOrder:
          type: 'object'
          required: ['status']
          properties:
            status:
              type: 'boolean'

Instead, $ref is seemingly silently treated as a literal field.