August 15, 2022

Merging `hyRefactor` with `hyAggregate` to create `hydrofab`

Change union_linestrings_geos to union_linestrings - remove rgeos dependency
Change union_polygons_geos to union_polygons - remove rgeos dependency
Change aggregate_network to aggregate_network_to_outlets
Change aggregate_catchments to aggregate_to_outlets
Change add_length to add_lengthm to avoid conflicts with add_lengthkm
remove onAttach message
add get_hydrofabric, read_hydrofabric, and write_hydrofabric
add prepare_network
add refactor that wraps refactoring workflow
add aggregate_along_mainstem
add collapse_headwaters
add aggregate_to_distribution
add add_nonnetwork_divides
add poi_to_outlet
add add_mapped_pois
add generate_lookup_table

TODO: add subsetting utilites.