Clears author, generation and title data just in case

src/main/java/net/knarcraft/bookswithoutborders/command/CommandClear.java

@@ -40,6 +40,9 @@ public class CommandClear implements TabExecutor {
             return false;
         }
         bookMeta.setPages("");
+        bookMeta.setAuthor(null);
+        bookMeta.setGeneration(null);
+        bookMeta.setTitle(null);
         heldBook.setItemMeta(bookMeta);
         BooksWithoutBorders.sendSuccessMessage(sender, "Book cleared!");
         return true;