(svn r7138) -Fix: [vehicle list windows] fixed a rare crash where having some (not all) vehicle list windows open for a player, that goes bankrupt would crash the game

-Codechange: closing all windows for a player will now loop all windows and close those, which got the player as caption instead of having a list of windows to close

window.h

@@ -613,6 +613,8 @@ void SendWindowMessageClass(WindowClass wnd_class, uint msg, uint wparam, uint l
 
 Window *FindWindowById(WindowClass cls, WindowNumber number);
 void DeleteWindow(Window *w);
+void DeletePlayerWindows(PlayerID pi);
+void ChangeWindowOwner(PlayerID old_player, PlayerID new_player);
 Window *BringWindowToFrontById(WindowClass cls, WindowNumber number);
 Window *FindWindowFromPt(int x, int y);