Lucy Nicholson / Reuters
Subtlety isn't the Irishman's strong suit.
JOHN GURZINSKI via Getty Images
Prepare for two solid months of world class trash talk.
LAS VEGAS, Sept 12 (Reuters) - Floyd Mayweather Jr. signed off from professional boxing as he had planned on Saturday, going out unbeaten and on his own terms as 'The Best Ever' after improving his ca...