St. Elmo’s Fire is ready for a reboot. Talk of making a sequel to the beloved 1985 movie is in the “very, very, very, very, very early stages,” co-star Rob Lowe, 60, confirmed this summer. Demi wants to do it. “From my understanding, pretty much everyone from the original cast” — which also includes Ally Sheedy, 62, Emilio, Mare Winningham, 65, Judd Nelson, 64, and Andrew McCarthy, 61 — “is in or at least open and interested,” Demi said recently. “It would be really fun.”…