Reuters: World leaders gather in New York this week to tackle a host of crises: the violence Islamic State militants are wreaking in Iraq and Syria, the exponential spread of the deadly Ebola virus in Africa and deadlocked negotiations on Iran's nuclear program. There is little hope the 193-nation UN general assembly will achieve much in the annual five-day marathon of speeches. But on the sidelines, US officials plan to lobby allies for pledges of concrete military assistance to help defeat Islamic State,...