title: Return dictionary instead of array in REST framework
body: <p>I am converting a set of existing APIs from tastypie to REST framework. By default when doing list APIs, tastypie returns a dictionary containing the list of objects and a dictionary of metadata, where REST framework just returns an array of objects. For example, I have a model called Site. Tastypie returns a dictionary that looks like </p>
  
  <pre>
  {
    "meta": 
      { ... some data here ...}, 
    "site": 
      [
        {... first site...}, 
        {...second site...}
        ...
      ]
  }
  </pre>
  
  <p>where REST framework returns just the array </p>
  
  <pre>
  [
    {... first site...}, 
    {...second site...}
    ...
  ]
  </pre> 
  
  <p>We are not using the metadata from tastypie in any way. What is the least invasive way to change the return value in REST framework? I could override list(), but I would rather have REST framework do its thing where ever possible.</p>