title: Python's json.load(sys.stdin) gets me u'...' instead of double quotes around Strings
body: <p>When I do:</p>
  
  <pre><code>import sys, json;
  import requests
  
  headers = {'Content-Type': 'application/json',
         'X-Parse-Application-Id': '...',
         'X-Parse-REST-API-Key': '...'}
  
  data = json.load(sys.stdin)
  for station in data["data"]:
      print station
      res = requests.post('https://api.parse.com/1/classes/test4', data=station, headers=headers)
  </code></pre>
  
  <p>I get</p>
  
  <pre><code>{u'city': u'London',
  ...
  }
  </code></pre>
  
  <p>And it's not a valid Json as when I try to POST it to Parse.com I'm getting</p>
  
  <pre><code>{"code":107,"error":"invalid JSON"}
  </code></pre>
  
  <p>and any JSON validator gives me <code>Error:Strings should be wrapped in double quotes.</code></p>
  
  <p>How to make a valid JSON of the <code>data</code>?</p>