Stabilise MoveToWorld (#4004)

* Stabilise MoveToWorld

* Fix comments and deprecate ScheduleMoveToWorld

* Enhanced thread safety for m_WorldChangeInfo

* Return unique_ptr from cAtomicUniquePtr::exchange

* cWorld now calls entity cEntity::OnAddToWorld and cEntity::OnRemoveFromWorld.

Allows broadcasting entities added to the world from the world's tick thread.
This also factors out some common code from cEntity::DoMoveToWorld and cEntity::Initialize.

As a consequence, cEntity::Destroy(false) (i.e. Destroying the entity without broadcasting) is impossible.
This isn't used anywhere in Cuberite so it's now deprecated.

* Update entity position after removing it from the world.
Fixes broadcasts being sent to the wrong chunk.

* Fix style

* cEntity: Update LastSentPosition when sending spawn packet

* Add Wno-deprecated-declarations to the lua bindings

* Kill uses of ScheduleMoveToWorld

src/ClientHandle.cpp

@@ -189,7 +189,7 @@ void cClientHandle::Destroy(void)
 				// If ownership was transferred, our own smart pointer should be unset
 				ASSERT(!m_PlayerPtr);
 
-				m_PlayerPtr = world->RemovePlayer(*player, true);
+				m_PlayerPtr = world->RemovePlayer(*player);
 
 				// And RemovePlayer should have returned a valid smart pointer
 				ASSERT(m_PlayerPtr);