Tim McGraw is getting ready for the annual NBC Macy’s Fourth of July Fireworks Spectacu lar. where he is going to be singing songs like “Southern Girl” and “Something Like That”. He chats with us offstage about the holiday and what he likes to do with his family. The show also features all-star performances by Mariah Carey, Taylor Swift, Selena Gomez and others. The two-hour show will be hosted by Nick Cannon of NBC’s “America’s Got Talent.” Grammy Award-winning artist Usher will curate the overa