Still more road merging

[nvkelso]

After #2008 I'm still seeing some road segments with all the same properties as separate features instead of a single merged feature.

340-new-v1.9-pre.mvt.zip

The highlighted geometries are one example from the above tile, where 3 of the 4 adjacent features all have the same properties and should be merged:

I suspect an order of operations where properties are being stripped after a merge instead of before a merge.

[nvkelso]

When I dissolve across all properties in QGIS I see a 56% reduction in feature count:

[nvkelso]

Let's also be more aggressive when names are dropped:

  - fn: vectordatasource.transform.drop_properties
    params:
      source_layer: roads
      start_zoom: 0
      end_zoom: 15
      # short-hand for "name" property in the list below means all name-like
      # properties.
      all_name_variants: true
      properties:
        - name
        - ref
        - all_networks
        - all_shield_texts
        - service
        - access
        - osm_relation
      where: >-
        (kind == 'highway' and zoom <  13) or    
        (kind_detail == 'trunk' and zoom <  13) or
        (kind_detail == 'primary' and zoom <  13) or
        (kind_detail == 'secondary' and zoom <  14) or
        (kind_detail == 'tertiary' and zoom <  14) or
        (kind_detail == 'motorway_link' and zoom <  15) or
        (kind_detail == 'trunk_link' and zoom <  15) or
        (kind_detail == 'primary_link' and zoom <  16) or
        (kind_detail == 'secondary_link' and zoom <  16) or
        (kind_detail == 'tertiary_link' and zoom <  16) or
        (kind == 'minor_road' and zoom < 15) or
        (kind == 'path' and zoom < 14) or
        (kind == 'rail' and zoom < 16) or
        (kind == 'ferry' and zoom < 16)

Modulo what's happening for aeroway in the other issue.

And check on the end_zoom param modulo max tile generation zoom. Right now the simplification zoom evaluation is sometimes for 16 but it wouldn't eval at zoom 15 right now.

[nvkelso]

Fixed via #2056 and other PRs.