Add time to releasedates?

[peteruithoven]

Currently it looks like we use releasedates to check whether there is a newer version. This is because it can't know which suffix (like -beta / -rc2 etc) is newer. But since it doesn't include a time we can only release one update per day?
It actually sees a newer version, but can_update is false:

{
  "data": {
    "can_update": false,
    "current_release_date": "20150616",
    "current_version": "0.10.6-rc1",
    "newest_release_date": "20150616",
    "newest_version": "0.10.6-rc2",
    "state_code": 1,
    "state_text": ""
  },
  "status": "success"
}