Stephen King’s ‘It’ is a beast of a book. Over its 1,000-plus pages, the novel follows a group of close-knit friends who do battle with a malevolent, child-killing force in their youth, only to reunite decades later to finish the job. It’s a messy, ambitious and insanely (perversely, even) detailed work. It feels unadaptable. But no one tell that to ‘True Detective’ director Cary Fukunaga, whose long-gestating adaptation is finally going before cameras next summer.