NEW YORK – The latest J.R.R. Tolkien project lasted six years, more than half as long as the author needed to complete his “Lord of the Rings” trilogy. Getting permission to release a book in electronic form can be as hard – or harder – than writing it. “The Tolkien estate wanted to be absolutely confident that e-books were not something ephemeral,” says David Roth-Ey, director of business development at HarperCollins UK, which announced last week that the late British author’s work – among the world’s most popular – would be available for downloads. “We were finally able to convince the Tolkien estate that the e-book is a legitimate, widespread format.” Tolkien’s in, but e-library still lacking