WayGenerator

addLine is called for any line feature that is being added to the FeatureCollection.

Inside generateIntersections, first traverse every line that was added and generate a new segment Feature at every intersection that we hit. Add these to Ways as we go. Intersections are spotted using the coordinate key (x + shr(y)). Put those features in two HashMaps a 'start' an 'end' one, again keyed by the coordinate key. Once we've traversed all of the lines we should have a Way for every segment between intersections. Now we generate the intersections and add the Ways directly to them. Let's do this in a separate class for now so that we can test it.