Better support for releases not sorted by time

[mindrones]

For example in d3-queue.json you can see that releases are not sorted by time:

  ...
  "time": {
    "modified": "2016-03-03T17:18:21.214Z",
    "created": "2016-01-23T05:00:32.836Z",
    "1.2.0": "2016-01-23T05:00:32.836Z",
    "1.2.1": "2016-01-25T05:38:16.791Z",
    "1.2.2": "2016-01-25T21:20:04.839Z",
    "2.0.0": "2016-01-27T18:12:57.616Z",
    "1.2.3": "2016-01-29T17:28:25.517Z",
    "2.0.1": "2016-01-29T17:35:39.783Z",
    "2.0.2": "2016-02-02T01:09:47.285Z",
    "2.0.3": "2016-03-03T17:18:21.214Z"
  },
  ...