Royal Shakespeare theatre, Stratford-upon-AvonJohn Douglas Thomas and Juliet Rylance reprise their New York roles as Othello and Desdemona, while Will Keen is all gripe and snipe as shaven-headed Iago With its fibs, delusions and mislaid props, Shakespeare's Othello is structured almost like farce " one that goes horribly wrong. In performance, cruel comedy and melodrama can lurch to the fore " but Tim Carroll's scul…