Core: Remove Player.h dependency from all the possible headers

src/server/game/Maps/MapManager.cpp

@@ -33,6 +33,7 @@
 #include "Language.h"
 #include "WorldPacket.h"
 #include "Group.h"
+#include "Player.h"
 
 extern GridState* si_GridStates[];                          // debugging code, should be deleted some day
 
@@ -439,4 +440,4 @@ void MapManager::FreeInstanceId(uint32 instanceId)
         SetNextInstanceId(instanceId);
 
     _instanceIds[instanceId] = false;
-}
+}