Core/Maps: Allow multi-threaded updates for all instances of a map, should increase performance

src/server/game/Maps/MapInstanced.cpp

@@ -64,7 +64,10 @@ void MapInstanced::Update(const uint32& t)
         else
         {
             // update only here, because it may schedule some bad things before delete
-            i->second->Update(t);
+            if (sMapMgr->GetMapUpdater()->activated())
+                sMapMgr->GetMapUpdater()->schedule_update(*i->second, t);
+            else
+                i->second->Update(t);
             ++i;
         }
     }

src/server/game/Maps/MapManager.h

@@ -148,6 +148,8 @@ class MapManager
         uint32 GetNextInstanceId() { return _nextInstanceId; };
         void SetNextInstanceId(uint32 nextInstanceId) { _nextInstanceId = nextInstanceId; };
 
+        MapUpdater * GetMapUpdater() { return &m_updater; }
+
     private:
         // debugging code, should be deleted some day
         void checkAndCorrectGridStatesArray();              // just for debugging to find some memory overwrites