Don't call duplicate interact air events. Fixes BUKKIT-5359

Previously we attempted to call interact events in cases that were missing
by modifying the arm swing logic. This, however, was too broad and started
triggering events in cases we already covered leading to duplicates. Since
the only case we can handle cleanly and the primary point of the previous
fix was fluids we now instead simply treat fluids as air for this check.
This also ensures we do not get duplicate events when the player is in a
fluid and hits a normal block, unlike the previous change.

This reverts commit 68b702f7 and replaces it with a better fix.
Allow AsynchronousExecutor.getSkipQueue() to pull tasks from the queue
Load all already generated chunks via async chunk system

Currently we use the async chunk loading system only when players trigger
chunk loading. If a chunk is loaded for any other reason it goes through
a separate codepath. This means if a player has trigged a chunk load and
before the chunk loads something else wants the same chunk we will load it
twice and throw away the second result. With this change we instead use
the sync processing feature of the AsynchronousExecutor to load the chunk
which will pull it out of the queue if it was already queued to load. This
means we only ever load a chunk once. Because chunk generation is not
thread safe we still fallback to the vanilla chunk loading system if the
chunk does not currently exist.
[Bleeding] Handle players disconnecting during respawn. Fixes BUKKIT-4327

Prior to this commit, a player disconnected during a respawn event would
remain in memory. This causes a ghosting issue of players in the slot
count and player list, as well as a reference leak.

This commit avoids re-adding the player to the player list (and world) if
they are disconnected. This ensures that the remainder of the respawn
logic is completed as well as ensuring a duplicate player is not left on
the server.

This commit also saves the player's file at the end of the method if they
have been disconnected to ensure that their next login is accurate to the
respawn event's actions. A player that was revived and disconnected will
reconnect as revived.
Implement SpawnReason.NETHER_PORTAL and DISPENSE_EGG. Fixes BUKKIT-3148

Previously any entities spawned through dispensers (monster eggs) or
by nether portals were given the incorrect SpawnReason of SPAWNER_EGG.
This made it impossible to distinguish what exactly happened in regards
to the creature being spawned.

A method in ItemMonsterEgg has been added to further fine tune reasons
for spawning creatures. This permits the DISPENSE_EGG reason to be used
correctly and accuratly as well as the NETHER_PORTAL reason due to how
BlockPortal spawns the mobs.

The redirected method, a(World, int, double, double, double), is still
called by the ItemMonsterEgg itself and therefore uses the default reason
of SPAWNER_EGG. This does not change previous behaviour.
Update clients when ItemFrame direction is set. Fixes BUKKIT-3371

Hanging entities are placed into the entity tracker and updates are sent
out to clients for the initial placement. Thereafter data watchers are
configured to monitor the item inside the frame. However, if the
direction the ItemFrame facing changes the entity tracker will not send
out updates.

This commit removes and recreates the ItemFrame entity in the same way
that was already done for Painting entities. This causes clients to
be updated appropriately.
[Bleeding] Correctly enchant books. Fixes BUKKIT-5302

Books can now recieve more than one enchantment.  As such, breaking out of
the loop after only 1 enchantment is applied is not the correct behavior.

This commit also reworks some of the logic surrounding the application of
enchantments to the item. By checking if the event doesn't add any
enchantments rather than if the original enchantments list is empty, the
application code is only reached if enchantments are applied, rendering
the "applied" boolean no longer necessary. The ItemStack's Item should only
be set once, so it is now set outside of the loop based upon whether or not
"flag" is true (with "flag" being whether or not the ItemStack's Item is a
book).
Implement banning API. Adds BUKKIT-3535

Previously no implementation existed to access various additional
information fields regarding bans. This implementation expands on the
information outlined in the sister Bukkit commit to provide access to
the Minecraft implementation of the ban system.

This implementation of the banning API contains 2 new classes which
provide access to the internal workings of the built-in banning
system within Minecraft.

The CraftBanEntry class simply supports the representation of an internal
Minecraft BanEntry object. The data that may be modified within this new
object must be manually saved to the list contained within the
CraftBanEntry using it's save() method.

The CraftBanList class supports the representation of an internal
Minecraft BanList object through proxy methods. These methods do
validation on the passed objects where needed to ensure safe input to the
backed Minecraft objects.

These changes additionally re-route the existing banning API to the newer,
more detailed, system. Functionality prior to this change still behaves
as documented by the contract defined by the methods changed.
[Bleeding] Implement Mojang command fallback system. Adds BUKKIT-5385
Match old alias behavior when migrating.

Previously the alias system would pass all arguments from the alias
to its command(s) implicitly. The new system requires arguments to be
explicitly passed so server owners can have more control over where and
how they are passed. To ensure this isn't a breaking change during the
migration from bukkit.yml to commands.yml we now add the $1- argument
to the alias commands to match the previous behavior.
Readd BlockPlaceEvent for half slab to full block. Fixes BUKKIT-5390
Add method to forget callbacks in AsynchronousExecutor
Handle removing entity while ticking. Fixes BUKKIT-1331

If a plugin causes an entity to be removed from the world while the
world is ticking entities the ticking loop gets out of sync and fails due
to trying to go beyond the end of the entity array. To ensure this doesn't
happen we store the loop position as a field so we can fix it up in the
entity remove method just like the tick method does when it removes an
entity.
Readd diff missed in the 1.7 update.
Hide message from connection throttle on startup. Fixes BUKKIT-5403
Rename Minecraft command permission nodes to meet fallback spec.
Add PlayerSelector.java for diff visibility.
Ignore player selectors if not a Command Block.
Update/improve configuration documentation.
Check if entity is in list before decrementing. Fixes BUKKIT-5404