Core/Vehicles

* Fixed crash happening when passenger died on vehicle he was controlling
* Fixed crash happening if vehicle control aura was removed before passenger is fully added to vehicle

Closes #7160
DB/Quests: Fix The Best of Intentions, closes #5716

Remove a bunch of incorrectly spawned NPCs and add some missing NPCs and GOs for quest Defiling the Defilers.
Script/Spell: Unlocking Zuluhed's Chains

Closes #996
DB/Loot: Correct Lootmode for some questitems (thx redsonja as well)

Closes #9382
Closes #9381
DB/SAI fix some event_flags and other conversion issues

Closes #9144
Core/Vehicles: Fixed a crash introduced in 2c169bcca51ca1b5cdbc73c9a4d402d46cdcfc15
Merge branch 'master' of github.com:TrinityCore/TrinityCore into 4.3.4