Warren Buffett has been selling stocks and stockpiling cash. But for the most part, he's leaving the Berkshire Hathaway portfolio intact. He's holding onto his favorites, even though he sold a large portion of Apple, and the portfolio is still dominated by financial stocks and dividend stocks.Amazon (AMZN -1.02%) is one of Buffett's smaller positions, and it wasn't his idea to buy it -- he said that one of Berkshire Hathaway's portfolio managers decided to buy it. It's been a valuable addition, up 127% over ...