Fixes problems with windows:

- Changed cPlayer:OpenWindow to accept a ref, tolua adds a nil check
- Close open lua window in destructor, to avoid dangling pointers

src/Entities/Minecart.cpp

@@ -1222,7 +1222,7 @@ void cMinecartWithChest::OnRightClicked(cPlayer & a_Player)
 	{
 		if (a_Player.GetWindow() != Window)
 		{
-			a_Player.OpenWindow(Window);
+			a_Player.OpenWindow(*Window);
 		}
 	}
 }

src/Entities/Player.cpp

@@ -1310,15 +1310,15 @@ cTeam * cPlayer::UpdateTeam(void)
 
 
 
-void cPlayer::OpenWindow(cWindow * a_Window)
+void cPlayer::OpenWindow(cWindow & a_Window)
 {
-	if (a_Window != m_CurrentWindow)
+	if (&a_Window != m_CurrentWindow)
 	{
 		CloseWindow(false);
 	}
-	a_Window->OpenedByPlayer(*this);
-	m_CurrentWindow = a_Window;
-	a_Window->SendWholeWindow(*GetClientHandle());
+	a_Window.OpenedByPlayer(*this);
+	m_CurrentWindow = &a_Window;
+	a_Window.SendWholeWindow(*GetClientHandle());
 }
 
 

src/Entities/Player.h

@@ -229,7 +229,7 @@ public:
 	// tolua_begin
 
 	/** Opens the specified window; closes the current one first using CloseWindow() */
-	void OpenWindow(cWindow * a_Window);
+	void OpenWindow(cWindow & a_Window);
 
 	/** Closes the current window, resets current window to m_InventoryWindow. A plugin may refuse the closing if a_CanRefuse is true */
 	void CloseWindow(bool a_CanRefuse = true);