fails:Time.utc handles microseconds
fails:Time.utc handles fractional microseconds as a Float
fails:Time.utc handles fractional microseconds as a Rational
fails:Time.utc ignores fractional seconds if a passed whole number of microseconds
fails:Time.utc ignores fractional seconds if a passed fractional number of microseconds
fails(travis):Time#utc? returns true if time represents a time in UTC (GMT)
