Merge branch 'master' into jgrpp-nrt

Merge NRT feature

# Conflicts:
#	docs/landscape.html
#	docs/landscape_grid.html
#	src/bridge_map.h
#	src/build_vehicle_gui.cpp
#	src/company_base.h
#	src/company_cmd.cpp
#	src/misc_gui.cpp
#	src/newgrf.cpp
#	src/newgrf_engine.cpp
#	src/pathfinder/follow_track.hpp
#	src/pathfinder/npf/npf.cpp
#	src/road_cmd.cpp
#	src/road_func.h
#	src/road_gui.cpp
#	src/road_map.h
#	src/road_type.h
#	src/roadveh_cmd.cpp
#	src/saveload/afterload.cpp
#	src/saveload/company_sl.cpp
#	src/script/api/script_bridge.cpp
#	src/table/newgrf_debug_data.h
#	src/tile_cmd.h
#	src/town_cmd.cpp
#	src/tunnel_map.h
#	src/tunnelbridge_cmd.cpp

src/command.cpp

@@ -75,6 +75,8 @@ CommandProc CmdBuildRoad;
 
 CommandProc CmdBuildRoadDepot;
 
+CommandProc CmdConvertRoad;
+
 CommandProc CmdBuildAirport;
 
 CommandProc CmdBuildDock;
@@ -298,6 +300,7 @@ static const Command _command_proc_table[] = {
 	DEF_CMD(CmdRemoveLongRoad,            CMD_NO_TEST | CMD_AUTO, CMDT_LANDSCAPE_CONSTRUCTION), // CMD_REMOVE_LONG_ROAD; towns may disallow removing road bits (as they are connected) in test, but in exec they're removed and thus removing is allowed.
 	DEF_CMD(CmdBuildRoad,    CMD_DEITY | CMD_NO_WATER | CMD_AUTO, CMDT_LANDSCAPE_CONSTRUCTION), // CMD_BUILD_ROAD
 	DEF_CMD(CmdBuildRoadDepot,           CMD_NO_WATER | CMD_AUTO, CMDT_LANDSCAPE_CONSTRUCTION), // CMD_BUILD_ROAD_DEPOT
+	DEF_CMD(CmdConvertRoad,                                    0, CMDT_LANDSCAPE_CONSTRUCTION), // CMD_CONVERT_ROAD
 
 	DEF_CMD(CmdBuildAirport,             CMD_NO_WATER | CMD_AUTO, CMDT_LANDSCAPE_CONSTRUCTION), // CMD_BUILD_AIRPORT
 	DEF_CMD(CmdBuildDock,                               CMD_AUTO, CMDT_LANDSCAPE_CONSTRUCTION), // CMD_BUILD_DOCK