KUWAIT (Reuters) - Donor countries have pledged more than $1.5 billion to aid Syrians stricken by civil war, U.N. Secretary-General Ban Ki-moon said on Wednesday after warning that the conflict had wrought a catastrophic humanitarian crisis. In a pointed message for Syria's leader, Ban told a fund-raising conference that President Bashar al-Assad bore primary responsibility to stop his country's suffering after nearly two years of conflict that have cost an estimated 60,000 lives. ...