Resolves: #1302497
    - Rebase to 2016a
      - America/Cayman will not observe daylight saving this year after all.
        Revert our guess that it would.
      - Asia/Chita switches from +0800 to +0900 on 2016-03-27 at 02:00.
      - Asia/Tehran now has DST predictions for the year 2038 and later,
        to be March 21 00:00 to September 21 00:00.  This is likely better
        than predicting no DST, albeit off by a day every now and then.