Edward Gardner is the UK’s “it” conductor of the moment, having made headlines with a production of John Adams’s controversial Death of Klinghoffer last year, and then winning appointment as principal conductor of the always tumultuous English National Opera. Now, he’s opening the famed Edinburgh Festival with a new production of Strauss’s massive opera, Elektra. “It is a big gig even for a musician whose career, at the moment, seems unstoppable.”