title: Fields as array when I select in elasticsearch
body: <p>I'm using ElasticSearch in my system and I have a question.</p>
  
  <p>When I use GET in this uri:</p>
  
  <pre><code>/dev/category/_search
  </code></pre>
  
  <p>I receive this:</p>
  
  <pre><code>{
  ...
  "title": "Sound",
  "slug": "sound",
  ...
  }
  </code></pre>
  
  <p>It's correct. But I have many fields in this query and I want to optimize this one.</p>
  
  <p>I GET this uri:</p>
  
  <pre><code>/category/_search?show_in_menu=true&amp;fields=title,slug
  </code></pre>
  
  <p>When I add the param fields, all fields are returning as array. In this example, return this:</p>
  
  <pre><code>"fields": {
             "slug": [
                 "Sound"
             ],
             "title": [
                 "sound"
             ]
         }
  </code></pre>
  
  <p>There is a way to return only the field intead of an array?</p>
  
  <p>Thanks!</p>