Correct missed diff on skeletons. Fixes BUKKIT-3912

Remapped by Srg2Source from Bukkit/CraftBukkit@0802c7e3be4e61e036e672cf6c2bbe1a47072bc3
Properly copy collection references in ItemMeta.clone(). Fixes BUKKIT-3913

When cloning an item, all references are copied to the new item. For
collections, this makes internal changes become visible in both the old and
new items.

In CraftMetaItem, clone was not making copies of the appropriate collections
and has been fixed for non-null values.

In CraftMetaEnchantedBook and CraftMetaPotion, clone was using possible empty
collection references and has been changed to explicitly null-check instead.

Remapped by Srg2Source from Bukkit/CraftBukkit@aaaac471f371e2b504df500f146792e8aa8584f1
Update to Forge 7.7.1.617

MinecraftForge/MinecraftForge@6fe69124563886da65895ed1a9196198fe1f6118
MinecraftForge/MinecraftForge@41ed59f42478ebecf48a9814773d4363be89cdfd
MinecraftForge/MinecraftForge@a7108bc2ffa185c13c41959ccddc7fbdde789025
MinecraftForge/MinecraftForge@b4116f1f316875697146388a0459a49cb47486bf
MinecraftForge/MinecraftForge@6b1c46cc4a74193b08c5df28caf8b700b1681518
Call appropriate event for zombies igniting players. Adds BUKKIT-3915

Remapped by Srg2Source from Bukkit/CraftBukkit@85b7b99bda8aee852850baf401ced0ebda768650
Call PotionSplashEvent even for no effects. Fixes BUKKIT-3618

When a splash potion has no applicable effects we currently do not call
PotionSplashEvent. This means plugins are unable to make custom
potions with reliable splash handling as they have to relicate the
functionality themselves.

With this commit we simply make the event fire regardless of the effects
on the potion.

Remapped by Srg2Source from Bukkit/CraftBukkit@b8f8ec0455b38d9663436c3b16a27891b77625b7