BOSTON — U.S. Senators Elizabeth Warren and Edward Markey called for changes to the Supreme Court — including the addition of four more members to the nine-member court — during a stop in Boston’s Copley Square on Monday.The Democrats also pushed for tougher ethics oversight following revelations of business transactions and travel involving Justice Clarence Thomas that Thomas did not disclose.Warren said the current court is undercutting the nation’s democratic principles.“They are …