Veronica G. Cardenas/AFP via Getty ImagesA man who attacked a Pennsylvania elementary school with a machete was found dead in his prison cell on Monday morning after serving 22 years of a 132- to 264-year sentence, according to authorities. William Stankewicz was 78. In Feb. 2001, he walked into North Hopewell-Winterstown Elementary School with a 2-foot-long machete, wounding 11 kindergarten students, two teachers, and the principal before he was eventually wrestled to the ground. The principal,