(solar-time-string): Rewritten.
(solar-adj-time-for-dst): New function.
(solar-sunrise-sunset, diary-sabbath-candles,
solar-equinoxes-solstices): Revised to use the rewritten and new fcns.
dependent list of season names. The names are "international"; i.e.,
`vernal' and `autumnal' are used consistently.
(solar-equinoxes-solstices): Use new constants, allowing southern
hemisphere reports to be meaningful.
(sunrise-sunset): Use `frame-width' instead of `screen-width'.
solar-equinoxes-solstices.
(calendar-time-display-form, calendar-latitude,
calendar-longitude): Moved from calendar.el.
(calendar-time-zone, calendar-standard-time-zone-name,
calendar-daylight-time-zone-name,
calendar-daylight-savings-starts, calendar-daylight-savings-ends):
Take default values from calendar-current-time-zone, instead of
being overwritten in open code if they were set to nil.
(solar-time-string): Subtract calendar-daylight-time-offset when
computing dst-ends. Avoid rounding errors when rounding time to
the nearest minute.
Universal Time (UT) to Coordinated Universal Time (UTC).
(solar-time-string): Use calendar-daylight-time-offset instead of
1 hr, and use calendar-daylight-savings-switchover-time instead of
midnight. Add an optional parameter to allow forcing the use of
standard or daylight savings time. Fix code so it works in
southern hemisphere (start of dst precedes end of dst in a
calendar year) and when dst either starts or ends in a calendar
year, but not both.
