Reuters: Hurricane Gustav gathered strength over the warm waters of the Caribbean on Friday roaring toward the Cayman Islands and the Gulf of Mexico on the third anniversary of Hurricane Katrina’s deadly strike on New Orleans. The storm, which killed up to 77 people in the Caribbean, plowed toward superheated waters south of Cuba where it could absorb enough energy to strengthen into a major hurricane before ripping through the heavy concentration of U.S. oil and natural gas platforms off …