Update visibility system

*visibility updates and ai relocations processed simultaneously for each grid
  *these operations now are not synchronized for different grids
  *some changes into structure of visibility notifiers

--HG--
branch : trunk

src/game/Unit.h

@@ -1734,6 +1734,7 @@ class Unit : public WorldObject
         bool canDetectInvisibilityOf(Unit const* u) const;
         bool canDetectStealthOf(Unit const* u, float distance) const;
         void SetPhaseMask(uint32 newPhaseMask, bool update);// overwrite WorldObject::SetPhaseMask
+        void UpdateObjectVisibility(bool forced = true);
 
         // virtual functions for all world objects types
         bool isVisibleForInState(Player const* u, bool inVisibleList) const;
@@ -1903,9 +1904,6 @@ class Unit : public WorldObject
 
         uint32 GetModelForForm(ShapeshiftForm form);
 
-        // relocation notification
-        void SetToNotify();
-
         void SetReducedThreatPercent(uint32 pct, uint64 guid)
         {
             m_reducedThreatPercent = pct;