Futures flat as countdown to Trump's inauguration begins

* Markets are also eyeing a raft of economic data and a speech by Federal Reserve Chair Janet Yellen. * After having driven Wall Street to record highs in a post-election rally, investors are on the sidelines as they wait for Trump's inaugural speech to get a better understanding of his policies. * With the fourth-quarter earnings season picking up pace, investors will be focusing on key companies including Dow components IBM and American Express , which are scheduled to report results after mar