Ken Burns’ upcoming six-part, 12-hour documentary “The American Revolution” doesn’t just tell the story of icons like George Washington or Benjamin Franklin. The series, which premieres Sunday on PBS, brings to life the ordinary people — teenagers, women, free black Americans, immigrants, and ne’er-do-wells — who history usually crops out of the frame. We all know the headliners of the Revolution . We’ve seen them haloed in oil paint, read about them in thousand-page biographies, and even