RAMALLAH, West Bank (Reuters) - Israeli-Palestinian talks on security coordination scheduled after a ceasefire summit meeting were postponed on Thursday because of a fresh outbreak of violence, Palestinian officials said. "Today's meeting with the Israelis has been postponed. The Israelis asked to cancel it because of mortar firing in Gaza earlier today," one senior official said. Palestinian militants fired dozens of mortar bombs into Jewish settlements in Gaza in a barrage they said avenged the killing of a Palestinian by Israeli army gunfire the day before. They denied that they were defying a ceasefire declaration by Palestinian President Mahmoud Abbas...