Update V 1.2 - This update hopefully fixes the flying books in the library, there are still a few shelves on which the books don't sit properly but none seem to fly around now. Having the library in it's own cell also helps. I have also added ambient sounds to the interiors for water and fire; the castle could be ghostly quiet at times.
Also note on Havok in cells having large number of objects (like a library with lots of books) - If you have a decent machine and also use software that boosts Skyrim performance you must set the latter to a max of 60fps; above that you will experience havok with havok