Echonest track profile requests always return an empty audio_summary
<p>I'm requesting <code>bucket=audio_summary</code> for songs that rank highly in hotttness.
The top 100 hotttessst songs all return <code>track.status: 'complete'</code> but the audio summary is always an empty object. </p>

<p>How do I get audio summary data like <code>time_signature</code> and <code>tempo</code>? Doesn't <code>track.status: complete</code> imply that this information should be included in the response?</p>

<pre><code>Can't Feel My Face 
https://developer.echonest.com/api/v4/track/profile?api_key=*****************&amp;format=json&amp;id=SOMVZDS14DDE5909E7&amp;bucket=audio_summary

  {
    "response": {
      "status": {
        "version": "4.2",
        "code": 0,
        "message": "Success"
      },
      "track": {
        "status": "complete",
        "id": "SOZOIDR14C02B654D4",
        "audio_summary": {}
      }
    }
  }
</code></pre>