LONDON (REUTERS).- A major London exhibition of treasures from the Prince of Liechtenstein’s collection has been canceled because of a dispute over the export of one of the prince’s paintings. The show was billed as one of the highlights of the 2010 season at the Royal Academy, and the prestigious gallery is now working on alternatives to fill its main galleries between September and December next year. “After many months of planning … we are of course very disappointed that the Prince of Liechtenstein has decided to cancel the exhibition,” a spokesman for the gallery