A day after their casino proposal was rebuffed by the town of Foxborough, New England Patriots owner Robert Kraft and casino mogul Steve Wynn expressed dismay at the setback but refused to back down from their plans for a casino near Gillette Stadium. “We’re disappointed with the Board’s decision to deny Foxboro taxpayers the due process they are entitled under the state’s gaming law,’’ Wynn Resorts and The Kraft Group said in a statement. “We have not made any decisions regarding next steps.’’