utc_rc_values nanosecond support

[Joshua Hoblitt]

Hi Dave,

Two questions:

1) When is fractional second support going to be dropped?

and

2) It just occurred to me that nanosecond precision is lost when converting between 
calendars.

It seems that it should be fairly trivial to add this support.

sub _calc_utc_rd

    needs support for utc_rd_nanos.  _normalize_nanoseconds already exists.

sub utc_rd_values

changed to:

    sub utc_rd_values { @{ $_[0] }{ 'utc_rd_days', 'utc_rd_secs', 'utc_rd_nanos' } }

I think thats it - but I haven't looked very hard.

I'll submit a patch against DT and the docs if you think this is worth doing.

Cheers,

-J

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