title: setting required on a json-schema array
body: <p>I am trying to figure out how to set <code>required</code> on my json-schema array of objects. The <code>required</code> property works fine on an object just not an array.</p>
  
  <p>Here is the items part of my json schema:</p>
  
  <pre><code>        "items": {
          "type": "array",
          "properties": {
              "item_id": {"type" : "number"},
              "quantity": {"type": "number"},
              "price": {"type" : "decimal"},
              "title": {"type": "string"},
              "description": {"type": "string"}
          },
          "required": ["item_id","quantity","price","title","description"],
          "additionalProperties" : false
      }
  </code></pre>
  
  <p>Here is the json array I am sending over. The json validation should fail since I am not passing a description in these items.</p>
  
  <pre><code>       "items": [
          {
              "item_id": 1,
              "quantity": 3,
              "price": 30,
              "title": "item1 new name"
          },
          {
              "item_id": 1,
              "quantity": 16,
              "price": 30,
              "title": "Test Two"
          }
      ]
  </code></pre>