Use anvil correctly when using 1.5 drop feature. Fixes BUKKIT-4027

When using the new feature in 1.5 to drop the item in any highlighted slot
on the anvil result slot it does not apply the full anvil code that picking
up the item does. This gives an item that has been combined/renamed/repaired
but does not cost the user any experience levels.
Add delay to hopper even if it doesn't do anything. Fixes BUKKIT-4061

If a hopper is unable to perform any action during a tick it attempts to do
so every tick from then on. Once it is able to do so it then sets a delay
before attempting to do something again. To avoid excessive CPU usage for
hoppers sitting idle we now apply this delay regardless of the success of
the action.