Wilton's Music Hall, LondonRichard Cant is superb as Merle Miller who takes a stand against homophobia in this clever retelling of his landmark essay Merle Miller, a distinguished mid-century American writer, lived in an actual glass house. When we meet him in this play, he's a man with an open secret. And he's about to take to his typewriter and throw some stones. A gay man in a doggedly straight age, Miller was a l…