Heat oil in a heat-proof casserole or Dutch oven. Stir in next 7 ingredients. Add chicken pieces and turn to coat with onion mixture. Arrange lemon wedges over top. Cover and simmer turning occasionally, 1 1/2 to 2 hours, or until very tender. Remove chicken to warm serving platter, arrange cooked lemon wedges on top and keep warm. Cook liquid, stirring, in casserole over high heat until reduced to a thick sauce. Add olives and heat through. Pour over chicken.