Perform anvil calculations when using 1.5 drop feature.

When using the new feature in 1.5 to drop the item in any highlighted slot,
the anvil result slot does not apply the full anvil calculation that picking
up the item does, including the experience calculation.

Remapped by Srg2Source from Bukkit/CraftBukkit@e4f2dd71526f40223f4fc5b20ecd29986dce9acc
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.

Remapped by Srg2Source from Bukkit/CraftBukkit@f5388e8f94e2cbab76c2255fd872c289e83100a0
Don't apply fall damage when cancelled. Fixes BUKKIT-4065

Remapped by Srg2Source from Bukkit/CraftBukkit@d37b640f711edf56681c39b218435c9aab5439b6