It's 10 a.m. in Tokyo and lines of grown men are already wrapped around the Saitama Super Arena to see one of the most exciting metal act around play tonight. No, not Metallica. Not Slipknot. This is a metal band centered around three teenage girls; this is Babymetal. Comprised of 17-year-old Suzuka "Su-metal" Nakamoto and 15-year-olds Yui "Yuimetal" Mizuno and Moa "Moametal" Kikuchi, the Japanese