Pittsburgh rocker Mike Stout keeps churning them out, now releasing his 20th CD, “Blue And Green in Black And White.” Stout, a union leader dubbed the World’s Grievance Man who specializes in songs of political and social justice songs, covers a wide range of topics here and all the genre bases, from bluegrass to rock, with blues, country and Irish in between. “One Big Union” is a Celtic-style rally anthem,…