Propagating changes about osm2streets HOT 4 OPEN

    - first look at whole network, then do dirty bit things
    - geometry says this looks like u-turn, fix it up
            - what changes now that we determine that?
    - transformations are like rawmap editor actions, higher level
    - cycleway snapping is a case where the collapsing might happen too early
            - how should collapsing actually work? keep the graph the same
            - low-level street network OSM node
            - Junction with 1+ nodes, uses pretrimmed distances
            - DC join needs to radically alter reference line of the Y shape
            
            - 3 levels of stuff?
                    - Junction is a full subgraph of stuff
                    - the intermediate thing is just where we currently collapse. movements here?
                            - the geometry for pretrimmed case is higher level, has access to lower level thing
                            - less state? the collapsed road isnt gone. just views on top of stuff
            - or simplify. if the transformation needs OSM level stuff, just do it before we collapse.