Osmnx

- fix errant print statement

- fix .osm xml output
- fix geopandas future compatibility

- fix get_nearest_edges search when not using a spatial index

- drop formal python 2 support
- refactor all modules for cleaner package organization
- make stats betweenness centrality compatible with networkx>=2.4
- allow configurable overpass and nominatim endpoints
- allow gdf_from_places to take a which_result list argument
- handle zero-division in street grade calculation
- better footprint relation handling
- improve network type queries for better filtering
- fix pois_from_polygon returning points outside polygon

- remove deprecated buildings module
- filter steps ways out of bike queries
- convert CRS-handling to proj4 strings
- save graph to xml-formatted .osm file
- minor refactoring

- deprecate buildings module and replace with generalized footprints module
- improve handling of multipolygon footprints
- new function to find nearest edge(s), given coordinates
- add "search," "reverse," and "lookup" nominatim queries
- use unprojected graphs for figure-ground plotting functions
- allow non-integer osmid values for custom data
- improve get_route_edge_attributes function
- improve color mapping by node/edge attribute value
- make bidirectional network types explicit
- networkx compatibility fixes to resolve warnings