Sync zoneinfo database with tzdata2016a from ftp://ftp.iana.org/tz/releases

Sync zoneinfo database with tzdata2016a from ftp://ftp.iana.org/tz/releases

* America/Cayman will not observe daylight saving this year after all.
    Revert our guess that it would.  (Thanks to Matt Johnson.)

* Asia/Chita switches from +0800 to +0900 on 2016-03-27 at 02:00.
    (Thanks to Alexander Krivenyshev.)

* 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.

* America/Metlakatla switched from PST all year to AKST/AKDT on
    2015-11-01 at 02:00.  (Thanks to Steffen Thorsen.)

* America/Santa_Isabel has been removed, and replaced with a
    backward compatibility link to America/Tijuana.  Its contents were
    apparently based on a misreading of Mexican legislation.

* Asia/Karachi's two transition times in 2002 were off by a minute.
    (Thanks to Matt Johnson.)

* The Theory and asia files now mention the 2015 book "The Global
    Transformation of Time, 1870-1950", and cite a couple of reviews.

* The America/Chicago entry now documents the informal use of US
    central time in Fort Pierre, South Dakota.  (Thanks to Rick
    McDermid, Matt Johnson, and Steve Jones.)