Songs have been dropped, dance routines booted out and the street-fights look nasty. This is a West Side Story for the Trump era, says the avant-garde superstar director Ivo van Hove likes it in America. Broadway rarely warms to avant-garde Belgian directors, but it has embraced this one, first for his blood-drenched A View from the Bridge, then for his unorthodox Crucible, which starred a large dog, and then for his…