swap RoadTypes enum to version given by Alberth, with StreetTypes and TramTypes, and methods to set / get / check those from the RoadTypes instance

substitute RoadNotTypes whilst patching, then replace later (RoadNotTypes won’t cause search term conflict with RoadTypes)

to patch RoadTypes, there are 78 places consuming RoadTypes enum

move the storage to m4 as part of this, and deprecate the two existing road/tram bits

most of the consumers of RoadTypes don’t look hard to patch

replace some checking of bits with ‘HasStreetType()’, ‘HasTramType()’ calls

do not at this stage try and handle multiple types of StreetType, TramType, assume only one of each

this is unfortunately quite a large patch

extend StreetType and TramType to support multiple types of each available (only one per tile)

support constructing multiple types

support incompatibility when routing

extend features to StreetTypes and TramTypes

catenary, with drawing support (bridges, tunnels etc)

blah

what is all the scripting support doing with RoadTypes?

??

split types in global construction menu

does this imply also splitting the construction toolbars?  Or leave it unified and use a flag, as now?

do this first, in a dedicated branch, to find out?