What would you do if you were pinned down by an 800-pound boulder, and no one knew where you were? In 2003, Aron Ralston had to answer that question. Today, our survival correspondent Blair Braverman is here to tell us the tale of the man, the myth, and the multitool.Blair Braverman tells us how the legendary story of one good dog is actually a story of two good dogs. Read Blair’s book, Small…