[8103] More wide use IsInWorld checks and delayed at teleport operations. Author: Ambal

* IsInWorld used to prevent return unexpected not in world objects.
    * Delayed operations need to process its in world state.

--HG--
branch : trunk

src/game/Unit.cpp

@@ -8338,7 +8338,7 @@ bool Unit::Attack(Unit *victim, bool meleeAttack)
         return false;
 
     // dead units can neither attack nor be attacked
-    if(!isAlive() || !victim->isAlive())
+    if(!isAlive() || !victim->IsInWorld() || !victim->isAlive())
         return false;
 
     // player cannot attack in mount state