Set current recipe to null when a recipe isn't found. Fixes BUKKIT-2311

Prior to this commmit the diff in 84dbc21aa71b96fd1d2ea40d624b536309118cde
was lost over the updates since. This commit restores the functionality
repaired in 84dbc21aa71b96fd1d2ea40d624b536309118cde.
Add BlockCake for diff visibility.
Fire FoodLevelChangeEvent when eating cake. Fixes BUKKIT-2242