“What the world needs now is another folk singer, like I need a hole in my head.” Great song, and maybe Cracker was right when the band released “Teen Angst (What the World Needs Now)” in 1992. But today, the world d-e-f-i-n-i-t-e-l-y needs another folk singer. And Danny Rose is just the right thumb-in-society’s eye troubadour for these times. The 25-year-old folk singer/songwriter from Brisbane, Australia, has studied the style — and look — of early ’60s folkies like an honor student. He cites Bob Dylan, Woody Guthrie and Phil Ochs as major influences. But he doesn’t need to tell us that. Just listen to his rhythmic acoustic guitar strums,…