Versatility, thy name is Greg White. He recently finished a remarkable, critically acclaimed one-man performance as Thurgood Marshall, the first African-American justice on the Supreme Court, in Thurgood at Ensemble Theatre. And he accomplished that on the heels of his appearance in Eugene O'Neill's Anna Christie, also at Ensemble, in which he played the grizzled Swedish seaman Chris Christopherson. In each, White brought a warmth and humanity to roles that resonated in completely different ways.