Corrections of zone.tab for CN entries

[yaoz at vidar.niaaa.nih.gov]

Hi,

Thanks for the effort to maintain the tz packages.

Recently, I've seen people complain that in file zone.tab,
entries regarding China (CN) are not right.  They are:

CN      +4545+12641     Asia/Harbin     north Manchuria
CN      +3114+12128     Asia/Shanghai   China coast
CN      +2934+10635     Asia/Chungking  China mountains
CN      +4348+08735     Asia/Urumqi     Tibet & Xinjiang
CN      +3929+07559     Asia/Kashgar    Eastern Turkestan

There are several problems: 1. City names are in old form.  Now
there is a standard way (pinyin) to write it and it should be
used; 2. Comments are not quite right.  This may due to
the historic reasons.  Because of these problems, when users in China
are presented a form to pick a time zone, they are very
confused.

To correct this, the first thing should be noted is that
there is only ONE timezone in China.  This is well documentd
in file asia.  Second, to reflect the current practice, zone.tab
may be modified as:

CN      +4545+12641     Asia/Harbin     Beijing Time - Heilongjiang
CN      +3114+12128     Asia/Shanghai   Beijing Time
CN      +2934+10635     Asia/Chongqing  Beijing Time - Sichuan
CN      +4348+08735     Asia/Urumqi     Beijing Time - Xinjiang
CN      +3929+07559     Asia/Kashi      Beijing Time - Xinjiang

Or just one Beijin Time entry.  But I really don't know how
zone.tab and asia files are related to each other.  So the
above changes should only be a reference.

Best regards,

Yao Zhang