CAIRO (Reuters) - Egyptian protesters scaled the walls of the U.S. embassy on Tuesday, tore down the American flag and burned it during a protest over what they said was a film being produced in the United States that insulted Prophet Mohammad. In place of the U.S. flag, the protesters tried to raise a black flag with the words "There is no God but God, and Mohammad is his messenger", a Reuters witness said. Once the U.S. flag was hauled down, some protesters tore it up and showed off pieces to television cameras. Others burned the remains outside the fortress-like...