[tz] attic data for the tz database

[Paul Eggert]

Lester Caine wrote:
>> This will be a smaller change to the database now, which I
>> assume is a good thing.
> 
> In which case we have to start setting up a second database

It's no big either way, so if you'd rather
have a larger attic and if Stephen doesn't care, let's
make it larger.  I'll send out a proposed patch shortly,
which creates the attic in zic input format, so that it
can be used to further populate the database if you like.
This is all still experimental, but at least the latest
experimental version has recovered the pre-1970 data that
people were concerned about.