The past four spring training columns have each covered the progress of a class-action lawsuit in which minor league players sought to obtain what Major League Baseball, supreme ruler of the minor leagues, was unwilling to provide: a living wage. Many minor leaguers earn less than $7,500 a year, some less than $3,000, but barring action by the Supreme Court, their suit appears concluded.The 9th U.S. Circuit Court of Appeals ruled last June that baseball’s exemption from antitrust laws extends to the minor leagues …