UNITED NATIONS (AP) — The U.N. chief appointed a new special envoy to Yemen as pressure grows to return to peace talks while fighting continues in the Arab world's poorest country. Benomar's four years of efforts fell apart amid the Houthi rebel uprising and the airstrike response, which has led to fears of a kind of proxy war between Saudi Arabia and its Sunni allies and Iran, a Shiite power that has supported the Houthis. The head of U.N.