The Firefly Music Festival will return in 2016 from June 16-19. This year's lineup includes Mumford & Sons, Kings of Leon, Florence & the Machine, Deadmau5, Disclosure, blink-182, Death Cab for Cutie, Tame Impala, M83, A$AP Rocky, Ludacris, Earth Wind & Fire, Fetty Wap, Flogging Mol…