[tz] Adding verified historic details

[Paul Eggert]

On 09/04/13 13:43, Lester Caine wrote:
> Is that good enough to merge? 

I'm afraid we can't add zones that differ only in pre-1970
dates until we can figure out how to filter them out in
the default case, as we aren't prepared for the
hundreds or thousands of new zones that would be feasible
if we opened the floodgates.  Zefram has one prototype for
filtering, which I really must get to at some point.