BY CAPRICE LAWLESS Hauling rocks. Nailing fence posts. Painting walls. Babysitting. Folding sweaters. Making photocopies. Cleaning horse stalls. Laying sod. Pouring coffee. Packaging candies. Watering plants. Driving UPS vans. Delivering pizzas. Delivering flowers. This is just a short list of what many of America’s 768,000 college teachers will be doing this summer to try to…