Core/Entities: Remove circular dependencies from GameObject headers, fixes *nix compile

--HG--
branch : trunk
extra : rebase_source : bcedd4aed81ad6fb72a13607cf954c11356bbfcc

src/server/game/Entities/GameObject/GameObject.cpp

@@ -18,7 +18,7 @@
 
 #include "Common.h"
 #include "QuestDef.h"
-#include "GameObject.h"
+#include "GameObjectAI.h"
 #include "ObjectMgr.h"
 #include "PoolMgr.h"
 #include "SpellMgr.h"