(svn r15340) -Fix [FS#2121]: changing town road layout in-game caused ugly road networks

-Fix: use a flag instead of TL_NO_ROADS to forbid towns to build roads. The flag is ignored during world generation, so there won't be 'ghost' towns anymore
-Feature: town layout is now stored per town, so it is possible to (manually) set different layout for each town

src/settings_gui.cpp

@@ -1097,6 +1097,7 @@ static PatchEntry _patches_economy_towns[] = {
 	PatchEntry("economy.bribe"),
 	PatchEntry("economy.exclusive_rights"),
 	PatchEntry("economy.town_layout"),
+	PatchEntry("economy.allow_town_roads"),
 	PatchEntry("economy.mod_road_rebuild"),
 	PatchEntry("economy.town_growth_rate"),
 	PatchEntry("economy.larger_towns"),