fix entity undo; amend constants

worldedit-core/src/main/java/com/sk89q/worldedit/internal/Constants.java

@@ -36,7 +36,7 @@ public final class Constants {
 
     static {
         NO_COPY_ENTITY_NBT_FIELDS = Collections.unmodifiableList(Arrays.asList(
-//                "UUIDLeast", "UUIDMost", // Bukkit and Vanilla 
+//                "UUIDLeast", "UUIDMost", // Bukkit and Vanilla //UUID values need to be set manully to a new UUID
                 "WorldUUIDLeast", "WorldUUIDMost", // Bukkit and Vanilla
                 "PersistentIDMSB", "PersistentIDLSB" // Forge
         ));