Activist investor Carl Icahn has just issued a Tweet sharing that he had a "cordial" dinner with Apple CEO Tim Cook last night where he pushed for an increased stock buyback of $150 billion. According to Icahn, the two will revisit the subject later this month. The stock buyback portion of Apple's capital return program was originally set at $10 billion when it was announced in March 2012, but in April of this year the company announced a significant increase to $60 billion as Apple has sought to