Transform syscall.Filetime to human-readable date

Here’s a work-around:

{{ $zerotime := time "1970-01-01" }}
{{ duration "nanosecond" $img.CreationTime.Nanoseconds | $zerotime.Add }}

I cleaner solution would be to expose a time.Unix implementation so that you could do:

{{ time.Unix 0 $img.CreationTime.Nanoseconds }}