(svn r1479) -Added highscore chart (accessible from the difficulty window) with top5 companies for a given difficulty (select the difficulty in the menu)

-Added endgame score on 1 jan 2051 where you are added to the highscore if sufficiently large points have been accumulated. Game is paused while
-These values are saved in hs.dat; added read/write functions for it
-Added code to delete all windows to show charts. There is one issue left: somehow a news-gui pops up in front of the the chart at the end of the game.

window.c

@@ -1520,6 +1520,13 @@ void DeleteAllNonVitalWindows(void)
 	}
 }
 
+/* Delete all always on-top windows to get an empty screen */
+void HideVitalWindows(void)
+{
+	DeleteWindowById(WC_MAIN_TOOLBAR, 0);
+	DeleteWindowById(WC_STATUS_BAR, 0);
+}
+
 int PositionMainToolbar(Window *w)
 {
 	DEBUG(misc, 1) ("Repositioning Main Toolbar...");