You're in high school and you bring along a gun to school. Fine. That's just plain commonsense. But in the first grade? Crazy! And that's just what happened at Cleveland Elementary School in the Excelsior District on Monday. According to the playground rumor mill, the kid was packing heat in his backpack. Turns out the gossip was true. School district spokeswoman Gentle Blythe clains that "the student said he thought it was a fake......