At 11, Claressa Shields decided she wanted to box, even with her father’s objections. At 17, she is the youngest female competing in the women’s boxing arena at the 2012 Olympics in London. “She's a beast. She's physically and athletically the most exciting thing to happen to women's boxing in a long time,” photographer Zackary Canepari said. Along with fellow producers Drea Cooper and Sue Jaye Johnson, Canepari has documented the teenage boxer as she trains, competes and lives the…