Long before “Lost,” a plane crash left survivors stranded on a tropical island. William Golding’s novel Lord of the Flies has twice been filmed. Director Harry Hook Americanized his 1990 version (out on Blu-ray) by making the middle-school age castaways into military academy cadets. A good ensemble of kid actors kept the plot on its arc as the teamwork of the first days leisurely descends into savagery and survival of the fittest (i.e. ruthlessness).