cut down the number of unnecessary calls to gettimeofday

lets get it right (from ist!dt)

Fixed (?) European DST rules, and added a special set for
Canada without the 74/75 peculiarities (Tilbrook says this is so...)

Add copyright

fix ctime(time 0), year > 2100 (can't be generated with long).

handle negative times

european timezone rules

include fixes

from robert

date and time created 80/12/21 16:39:33 by wnj