Anupama Chandrasekhar argues, with humour and invention, against political extremism The young Indian man stepping towards us on the vast Olivier stage is unremarkable enough, slight and boyish in manner. When he speaks he is direct, even cheeky: he wants us to like him. But this is Nathuram Godse, Gandhi's blood-stained murderer. He surely has a tough task ahead if he is going to persuade his listeners that he had t…