Correctly fire VehicleExitEvent. Fixes BUKKIT-3761

This change makes it so that EntityHuman#setPassengerOf(Entity) invokes
its parent method when leaving vehicles so that VehicleExitEvent is fired
for players leaving vehicles.

This change also fixes BUKKIT-2110, making it so VehicleExitEvent
correctly handles cancellation. The implementation of VehicleExitEvent
completely ignored the cancellation state of the event, making it so that
cancelling the event had no effect.  Cancelling a VehicleExitEvent now
causes the entity to remain inside of the vehicle, with no visual stutter.
Use ambient setting of potion effects. Fixes BUKKIT-4357 and BUKKIT-3653

This changes livingEntity.addPotionEffect(PotionEffect, boolean) to
construct the MobEffect using the constructor that includes the ambient
setting as supplied by the PotionEffect

This also changes livingEntity.getActivePotionEffects() to construct the
PotionEffects using the ambient setting supplied by the MobEffects.
Add API to control scaled health. Adds BUKKIT-4590

This commit implements the ability to set the scale of hearts that the
client renders.  When the Packet44UpdateAttributes packet is sent, the
max health attribute is replaced with a scaled version, to preserve the
scaled health illusion clientside.

In order to accurately display the scaled health for players, a true
health is stored within CraftPlayer, and the datawatcher now stores the
scaled health. The getHealth() method for players still returns their
true health.

Changed setHealth() within EntityLiving to appropriately handle health
for instances of EntityPlayer. Inlined a call to
setHealth(getMaxHealth()) within the EntityLiving constructor to work
around CraftEntity instantiation.

Additionally fixes the health values sent when eating food within
FoodMetaData and ItemFood, which previously sent the unscaled health;
this commit alters them to send the properly scaled health.

Additionally fixes BUKKIT-4535, BUKKIT-4536, and BUKKIT-4127
Check interactable items before event. Fixes BUKKIT-4576

Items that cause entities to change state, including tags, chest, and
leashes, do not update the client properly following the firing of
PlayerInteractEntityEvent. This change makes the item checks occur
before the event fires, to concur with the client's assumptions.
Fix CraftBukkit diffs
Store owning Horse in horse inventory. Fixes BUKKIT-4586
Restore CraftBukkit diff in ItemDye. Fixes BUKKIT-4493

Change ItemDye to pass the EntityHuman for StructureGrowEvent again.
Store item attributes. Addresses BUKKIT-4523
Fix NBT token for attribute names. Addresses BUKKIT-4483
Revert "Correct vehicle movement issues." Fixes BUKKIT-4565

This reverts commit 3d906d134417cfeefe7f71b916fee4d105e7650f.

Conflicts:
	src/main/java/net/minecraft/server/EntityTrackerEntry.java
Restore diff missed in 4176258a836062b22ac46919aefa5cc36fae78f2
Revert to 1.5 despawning behaviour for Ocelots and Wolves. Fixes BUKKIT-4449