WASHINGTON (Reuters) - President George W. Bush left on Friday for a holiday weekend with his longtime friend Don Evans amid speculation that the former commerce secretary was a top candidate to succeed Treasury Secretary John Snow. The Wall Street Journal online reported that Evans had emerged as the front-runner for the Treasury post. A Republican with close ties to the White House also told Reuters that he believed Evans was the leading candidate. A barrage of media stories in the past two days have suggested that Snow may leave within a month and people with close ties to the...