title: Make ordered dict default?
body: <p>Is it possible to make default dict literal to create ordered dicts not unordered ones?</p>
  
  <p>I would like to type complex nested configs like:</p>
  
  <pre><code>config = {
     'train': {
         'speed': 0.001,
         'initial_values': [1, 2, 3]
     },
     'model': {
  ...
     }
  }
  </code></pre>
  
  <p>and an idea to write a mess of brackets</p>
  
  <pre><code>config = OrderedDict([(
      'train', OrderedDict([(
         'speed', 0.001), (
         'initial_values', [1, 2, 3])]),(
      'model', OrderedDict([(
  ...
  </code></pre>
  
  <p>is absolutely unaplicable.</p>
  
  <p>Please no phylosophy about why my wish is bad.</p>
  
  <hr>
  
  <p>Ok, currently I would write somethong like:</p>
  
  <pre><code>def od(*args):
     return OrderedDict([(args[i], args[i+1]) for i in range(0, len(args), 2)])
  
  config = od(
      'train', od(
          'speed', 0.001,
          'initial_values', [1, 2, 3]
       ),
       'model', od(
      ...
       )
  )
  </code></pre>