A pair of shareholder-pleasing measures announced after market close Friday were powering the stock of Western Union (WU 4.00%) higher on Monday. Focused on news of a hefty share buyback program announced by the company, investors piled into the stock, boosting its price by 4% on the first trading day of the new week. That was more than good enough to beat the 0.4% rise of the S&P 500 (^GSPC 0.38%).Of share buybacks and dividend payoutsWestern Union's board of directors has authorized a $1 billion common st ...