(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.c

@@ -9,6 +9,7 @@
 #include "network.h"
 #include "network_data.h"
 #include "network_server.h"
+#include "engine.h"
 
 extern void StartupEconomy();
 extern void InitNewsItemStructs();
@@ -182,6 +183,13 @@ void ConvertGroundTilesIntoWaterTiles();
 
 void InitializeGame()
 {
+	// Initialize the autoreplace array. Needs to be cleared between each game
+	int i;
+	for (i = 0; i < 256; i++) {
+		_autoreplace_array[i] = i;
+	}
+	AddTypeToEngines(); // make sure all engines have a type
+	
 	SetObjectToPlace(1, 0, 0, 0);
 
 	_pause = 0;