Usher-ing in the 4th

Usher really likes fireworks — from at least 200 feet away. “This year, I’m not burning my thumbs,” he quips. “And I’m not going to break my neck trying to get away from that firework that I lit. ’Cause I try that every year — to do the big firecracker in my backyard where I light the wick, or you gotta light five of them and run away from them before it shoots off. I tried that s - - t, it didn’t work.” The 34-year-old R&B singer, who recently wrapped up a stint as a coach on “The Voice,” is taking the reins as “curator” of this year’s Macy’s Fourth of July Fireworks. The...