AllStackable

Thanks luaanon for implementing these fixes:

1. fix various unexpected behaviors of using a stack of items that are made stackable by this mod.

2. fix the entire stack of buckets (water, lava, etc) being replaced by a single empty bucket by the dispenser.

3. prevent equipping more than one saddle for a horse.

4. fix using a stack of discs on the jukebox

5. fix the entire stack of books and quill's being replaced with a single written book when signed