Allow directly recursive maps and arrays in Schema

```json
{
  "$ref": "#/definitions/Foo",
  "definitions": {
    "Foo": {
      "type": "object",
      "properties": {
        "bar": {
          "$ref": "#/definitions/Bar"
        }
      },
      "title": "Foo"
    },
    "Bar": {
      "type": "object",
      "additionalProperties": {
        "$ref": "#/definitions/Bar"
      }
    }
  }
}
```