Tony Kushner's epic "Angels in America" was a sensation on Broadway, winning multiple Tony Awards. An HBO film version followed, starring Al Pacino, Emma Thompson, and Mary-Louise Parker. Now "Angels in America," the opera, comes to Boston. The new work, by composer Peter Eotvos, had its world premiere in Paris. It makes its US premiere in an Opera Unlimited production at the Boston Center for the Arts' Stanford Calderwood Pavilion, June 16-24.