Fire VehicleEnterEvent for loaded chunks only. Fixes BUKKIT-3831
Implement InventoryMoveItemEvent. Adds BUKKIT-3765

This makes droppers, hoppers and hopper minecarts fire an
InventoryMoveItemEvent whenever an item is being moved from or to another
inventory.
Identify outside slot independent of inventory type. Fixes BUKKIT-2768
Include ThrownPotion in spawn methods. Adds BUKKIT-2542
Add check for Thorns damage - Fixes BUKKIT-3505