[tz] Fractional seconds in zic input

[Kim Davies]

Quoting John Hawkinson on Monday February 05, 2018:

> I think it is a very serious workflow problem that these potentially
> destabilizing changes are committed to the tz source tree prior to any
> discussion.

What is the expectation of the master branch of Paul's repository? Paul
has repeatedly referred to it as his experimental repository. If there
is a mismatch of expectations and folks are relying upon it for more
than that, I think that needs to be clarified.

kim