Billionaire, Opel heir, philanthropist, documentary filmmaker and renowned art collector Gunter Sachs shot himself in the head last month in his home in the exclusive Swiss Alpine restort Gstaad. He was the third husband of Brigitte Bardot, whom he married July 14, 1966, in an eight minute ceremony in Las Vegas.  The day after they met, he flew his helicopter over her villa in St. Tropez and dropped a hundred red roses.   "It was love at first sight," he said. "I met her in a restaurant and when we spoke, it was as though lightning had...