[tz] uniform time in Switzerland in second half of 19th century

[Paul Eggert]

Thanks for looking into that.  It confirms that Bern time was not
exactly GMT+0:30, though we still don't know what it was;
our current value (derived from one of the Shanks values) is probably
wrong by a few seconds.  It also confirms my suspicion that the 1894
transition was messy, but it suggests that our 1894 transition
date of June 1 is correct for Zurich, as my guess is that Zurich was not
one of the recalcitrant cantons (though it'd be nice to confirm this).
It'd also be helpful to know what time of day the 1894 transition
was; we're currently guessing 00:00.  And of course this helps only
with the 1894 transition; for the circa-1855 transition we're still
at sea.

In looking into this I found an old bug report from you that zic.8
disagrees with what's currently in 'europe'; I'll fix this shortly.
Sorry about that.

http://mm.icann.org/pipermail/tz/2011-August/008722.html