WASHINGTON — The White House is getting ready for the big holiday barbecue and fireworks show at 1600 Pennsylvania Avenue. President Barack Obama and first lady Michelle Obama returned from Camp David in time to host the Independence Day celebration. The Obamas have invited about 1,200 military families for the festivities Saturday night. The loud sounds of the Foo Fighters carried across the White House's South Lawn as the rockers rehearsed. During the presidential campaign last ye