Signature Theatre in Arlington, Virginia mounts an impressive and solid production of Kander and Ebb’s “The Scottsboro Boys”, a satirical minstrel show presentation of the harrowing story of one of the most disgraceful episodes in American history.  Musical theatre fans in the D.C.-metro area should flock to this regional premiere of an extraordinary and underappreciated musical.  It’s an important “must see” of the season, and well-worth the visit.