title: Elasticsearch return nested objects without their parents
body: <p>I have an index that looks like this:</p>
  
  <pre><code>{
      "mappings":{
          "authors":{
              "properties":{
                  "books":{
                      "type":"nested",
                      "properties":{
                          "title":{"type":"string"},
                          "firstSentence":{"type":"string"},
                          "isbn":{"type":"string"},
                          "publishDate":{"type":"date"},
                      }
                  },
                  "firstName":{"type":"string"},
                  "lastName":{"type":"string"}, 
                  "birthday":{"type":"date"},
                  }
             }
  }
  </code></pre>
  
  <p>I am querying this index through a Java client. For this query, I don't care about the authors; all I want to get back are books. For instance, I would like to find all books with the word "Hello" in the title and in the first sentence. </p>
  
  <p>Currently, I use a nested query that returns a list of authors, and then I manually parse that list to get the books. Is there a way to get Elasticsearch to directly return a list of books? I am using Elasticsearch version 1.5.2, and Jest 0.1.6</p>