DST law changes in Kemerovo and Novosibirsk.  Historical corrections for
Azerbaijan, Belarus, and Morocco.  Asia/Novokuznetsk and Asia/Novosibirsk
now use numeric time zone abbreviations instead of invented ones.  Zones
for Antarctic bases and other locations that have been uninhabited for
portions of the time span known to the tzdata database now report "-00"
rather than "zzz" as the zone abbreviation for those time spans.

Also, I decided to remove some of the timezone/data/ files that we don't
use.  At one time that subdirectory was a complete copy of what IANA
distributes in the tzdata tarballs, but that hasn't been true for a long
time.  There seems no good reason to keep shipping those specific files
but not others; they're just bloating our tarballs.