Core/Wintergrasp: finish implementation for battlefields. this is highly experimental enable at you're own risk. will almost definatly cause issues with the wintergrasp patch floating around

src/server/game/Entities/Unit/Unit.cpp

@@ -57,6 +57,8 @@
 #include "MoveSpline.h"
 #include "ConditionMgr.h"
 #include "UpdateFieldFlags.h"
+#include "Battlefield.h"
+#include "BattlefieldMgr.h"
 
 #include <math.h>