Core/Game: Include cleanup part 5

* ObjectMgr.h
* Player.h
* Unit.h
* G3D should no longer propagate everywhere from Spline/MotionMaster

src/server/game/Handlers/LFGHandler.cpp

@@ -19,6 +19,7 @@
 #include "Group.h"
 #include "LFGMgr.h"
 #include "Log.h"
+#include "ObjectAccessor.h"
 #include "ObjectMgr.h"
 #include "Opcodes.h"
 #include "Player.h"