Cityseer

Adds a method `nx_generate_vis_lines` for generating line string representations for nodes - this is intended for visualisation purposes. Bumps documents.

Version bump wrapping several minor changes related to tweaking graph cleaning settings and updating the io method for OS Open Roads loading (due to changes to the downloadable file structure).

Shortens name for `generic_edges_geopandas_from_nx` to `geopandas_from_nx`

Adds `generic_edges_geopandas_from_nx` which allows exports of edge geometry from `cityseer` compatible `networkX` graphs.

Currently, accessibility computations will return a count and distance weighted count of accessible locations within a given distance threshold. This update also exposes the nearest distance to a given landuse from a given node.

See the [london_centralities](https://github.com/benchmark-urbanism/cityseer-examples/blob/main/notebooks/london_centralities.ipynb) notebook for an example.

Re-exposes graph cleaning options for downloading OSM; minor fixes to GeoPandas import workflows