The first black woman to be nominated for a best director Golden Globe has been a pioneer all her life – and her new film, about Martin Luther King Jr, is uncannily in tune with an America once again riven by raceFreedom Journey 1965: Selma to Montgomery March in picturesIf certain films are of the moment, Selma seems like divine intervention; it is set to hit cinemas as protesters across the US rally against the mistreatment of black people by police officers.