GMTOffsetFromTz: Determine time offset from timezone
Description
Determine time offset from timezone
Usage
GMTOffsetFromTz(tz)
Arguments
tz
a timezone, e.g. UTC.
Value
Number of hours in offset, e.g. AST yields 4.
Details
The data are from
http://www.timeanddate.com/library/abbreviations/timezones/ and
were hand-edited to develop this code, so there may be errors. Also,
note that some of these contradict; if you examine the code, you'll
see some commented-out portions that represent solving conflicting
definitions by choosing the more common timezone abbreviation over a
the less common one.