Wall Street futures pointed to flat open on Tuesday in a session with few references as investors remained on hold ahead of key appearances from President-elect Donald Trump and Federal Reserve (Fed) chair Janet Yellen along with the kick off of the fourth quarter earnings season later in the week.The blue-chip Dow futures lost 2 points, or 0.01%, by 7:01AM ET (12:01GMT), the S&P 500 futures fell less than a point, or 0.01%, though the tech-heavy …