[tz] Fractional seconds in zic input

[Paul Eggert]

Tom Lane wrote:
> The original idea of adding the fractional seconds to the source files,
> and then dropping them again on output, sounded about right from here.

That's all that's been proposed for tzdb. I'm not proposing any change to the 
binary output files, just to the source files. I think you may have 
misunderstood comments about source files to be comments about binary files.