An obsession more than just a pet project, the decade-long history of “Nerone” is but an imperfect indicator of the gargantuan scale Arrigo Boito envisioned for his imperial tragedy. The opera is an unwieldy amalgamation of music that–like the scapigliatura movement itself–occupies a liminal space: neither conformist nor truly progressive, but somehow perpetually discontent. “Nerone” very much fits the {…}