By Trevor Hunnicutt, Patricia Zengerle and Jarrett Renshaw WASHINGTON (Reuters) – Democrat Joe Biden was sworn in as president of the United States on Wednesday, vowing to end the ‘uncivil war’ in a deeply divided country reeling from a battered economy and a raging coronavirus pandemic that has killed more than 400,000 Americans. With his hand on a five-inch thick heirloom Bible that has been in his family for more than a century, Biden took the oath of office administered by U.S. Chief Justice John Roberts that binds the president to “preserve, protect and defend the Constitution of the Unit…