Green Day's Billie Joe Armstrong is headed to treatment for substance abuse. Sunday's announcement by the band's rep comes after the rock frontman had a meltdown onstage at the iHeart Radio Music Festival in Las Vegas. In a clip that has gone viral, Armstrong profanely complained that the band's time was being cut short, then smashed his guitar. In a statement to The Associated Press, the band apologized for the incident and said their set was not cut short by Clear Channel, the host of the tw