ASSOCIATED PRESS — PHILADELPHIA City Council voted unanimously Thursday to place a referendum on the primary ballot that, if passed, could stop construction of two casinos along Philadelphia’s waterfront. Members voted 17-0 in favor of asking voters in the May 15 primary whether the city charter should be amended to ban the building of casinos within 1,500 feet of homes, churches and schools.The decision brought simultaneous cheers and boos from hundreds of casino opponents and supporters who were part of a standing-room-only crowd in council chambers. SugarHouse and Foxwoods plan to build slots casinos along the riverfront. SugarHouse plans to build just north of the Ben Franklin Bridge, while Foxwoods plans to build less than two miles away in South Philadelphia.