title: array unintentionally gets converted to object with supertest
body: <p>the array bellow (query.conditions) gets converted to an object somehow,
  any idea why and how I can prevent it ?</p>
  
  <p>The request:</p>
  
  <pre><code>          supertest(options.url)
              .get('/api/action')
              .expect(200)
              .query({
                conditions: 
                  [
                    { 'user' : user._id },
                    { 'type' : 14 },
                    { 'what' : 4 },
                  ]
              })
  </code></pre>
  
  <p>What the server gets:</p>
  
  <pre><code>{
    "conditions": {
      "user": "5592cc851f3febd016dae920",
      "type": "14",
      "what": "4"
    }
  }
  </code></pre>