I updated to 0.6.0 this morning. I removed two bookshelves, and put two stone cutters in their place. I placed the bookshelves elsewhere. I went mining, and came back up. The stone cutters were still there. I exited out of my world, then I left the game. When I came back, the stone cutters and new bookshelves were gone, and the bookshelves were back in there original place. But, I got two extra bookshelves in my inventory as well. This has happened to me multiple times so far, but I have not gotten any more bookshelves. In the picture, where the bookshelves are is where I have been trying to place Stonecutters.