TrinityCore: Added Vehicle Support

WotLK/Cataclysm: Merged DBCStores.h from MaNGOS changes here: https://github.com/eluna-dev-mangos/ElunaCoreTbc/commit/7e8581fe222c6cfca9228d61b36fad93d251350f

Possible crash fix and updated HookMgr with the latest GetDialogStatus changes. Closes https://github.com/ElunaLuaEngine/Eluna/issues/50

- Vehicle Hooks -

 RegisterVehicleEvent(eventId, function)

 OnInstall

 OnUninstall

 OnReset

 OnInstallAccessory

 OnAddPassenger

 OnRemovePassenger

- Vehicle Methods -

 GetBase

 GetAvailableSeatCount

 GetCreatureEntry

 GetPassenger

 HasEmptySeat

 IsVehicleInUse

 InstallAccessory

 ApplyAllImmunities

 AddPassenger

 EjectPassenger

 RelocatePassengers

 RemoveAllPassengers

 RemovePassenger

 RemovePendingEventsForPassenger

 Reset

Also removed Vehicle methods from the UnitMethods file and added a new UnitMethod

 - New UnitMethod -

 GetVehicle() -- Returns the unit's vehicle (if it is a vehicle)

Cataclysm changes will come soon enough.