(svn r1323) Adding autoreplace feature

This feature works much like autorenew, but it will get you a new engine type instead of a new one of the same type. Once 
ordered, it will automatically replace the engines while they visits a depot. The GUI for setting this up have been added on the 
vehicle overview windows
Note: autorenew is now autoreplace, but to the same engine type
Nice new features, that was added to make this possible
- windows can now have two independant vertical scrollbars
- CMD_SHOW_NO_ERROR have been added as a flag for DoCommandP. It will make it do the action instead of showing the red box with 
estimated costs even if shift is pressed
- fixed problem where enginetypes where not initialized when loading a game. It's now done in InitializeGame()

misc_gui.c

@@ -692,6 +692,14 @@ void SetVScrollCount(Window *w, int num)
 	if (num < w->vscroll.pos) w->vscroll.pos = num;
 }
 
+void SetVScroll2Count(Window *w, int num)
+{ 
+	w->vscroll2.count = num;
+	num -= w->vscroll2.cap;
+	if (num < 0) num = 0;
+	if (num < w->vscroll2.pos) w->vscroll2.pos = num;
+}
+
 void SetHScrollCount(Window *w, int num)
 {
 	w->hscroll.count = num;
@@ -700,7 +708,6 @@ void SetHScrollCount(Window *w, int num)
 	if (num < w->hscroll.pos) w->hscroll.pos = num;
 }
 
-
 int HandleEditBoxKey(Window *w, int wid, WindowEvent *we)
 {
 	byte *p;