Warren Buffett laid out a plan to "step up" the pace of giving away his $149 billion estate to his children's foundations, while still allowing for a short period that lets Berkshire Hathaway shareholders gain confidence in incoming CEO Greg Abel.Buffett, in a Thanksgiving letter that will become an annual tradition, said he needs to accelerate the disbursement of his Berkshire stock to his three children's foundations because of their own advanced ages and that by doing so it will "improve the probability ...