BEIRUT (Reuters) - The United Nations peace envoy to Syria said on Tuesday that Syrian officials had given him positive signals on a U.N. proposal for a local truce in the **rthern city of Aleppo, a main battleground in Syria's three-year-old war. Speaking in a news conference in Damascus after meeting President Bashar al-Assad and the Syrian foreign minister, Staffan de Mistura said the government's initial response to the proposal "was of interest, and constructive interest". Assad had also been quoted on Monday as saying the proposal was worth studying. ...