Arrays in JSONSchema do not contain `items` field

Hey,

Using the example blueprint, with master (and overriding protagonist to version 1.3.0-dev.0), I'd expect the output JSONSchema to be the same as the [example render](http://htmlpreview.github.io/?https://raw.githubusercontent.com/danielgtaylor/aglio/blob/master/examples/default.html).

Right now, I get a discrepancy in the `200 Response` in the `GET /notes` endpoint.

**Expected:**

``` json
{
"type": "array",
"items": {
"type": "object",
"properties": {
"id": {
"type": "number",
"description": "Unique identifier"
},
"title": {
"type": "string",
"description": "Single line description"
},
"body": {
"type": "string",
"description": "Full description of the note which supports Markdown."
}
},
"required": [
"id",
"title"
]
},
"$schema": "http://json-schema.org/draft-04/schema#"
}
```

**Actual:**

``` json
{
"$schema": "http://json-schema.org/draft-04/schema#",
"type": "array"
}
```