title: exclude _id and _index field in elasticsearch result data
body: <p>there are 5 fields in each document if simply hit the api. but i want only these two fields(user_id and loc_code) so I mentioned in fields list. but still it return some unnecessary data like _shards,hits,time_out etc.</p>
  
  <p>making POST request in postman plugin in chrome using below query</p>
  
  <pre><code>&lt;:9200&gt;/myindex/mytype/_search
  {
      "fields" : ["user_id", "loc_code"],
      "query":{"term":{"group_id":"1sd323s"}}
  }   
  </code></pre>
  
  <p>// output</p>
  
  <pre><code> {
          "took": 17,
          "timed_out": false,
          "_shards": {
              "total": 5,
              "successful": 5,
              "failed": 0
          },
          "hits": {
              "total": 323,
              "max_score": 8.402096,
              "hits": [
                  {
                      "_index": "myindex",
                      "_type": "mytype",
                      "_id": "&lt;someid&gt;",
                      "_score": 8.402096,
                      "fields": {
                          "user_id": [
                              "&lt;someuserid&gt;"
                          ],
                          "loc_code": [
                              768
                          ]
                      }
                  },
                 ...
              ]
          }
      }
  </code></pre>
  
  <p>but I want only documents fields(two mentioned fields) neither I want _id,_index,_type. is there any way to do so </p>