Fort Lauderdale builder Levitt and Sons, developer of the first postwar suburb, will wind down its operations and liquidate, according to court papers filed last week. The plan is subject to bankruptcy court approval. Levitt and Sons filed for bankruptcy protection last fall as the pressures of unsold inventory and falling home prices gutted the building industry. Levitt pioneered postwar development in 1949 when it built the New York suburb of Levittown on Long Island. Last year, it bailed out of the 331-acre Seasons at Tradition project in Port St. Lucie; it now has no developments underway in South Florida.