new polygon-to-polygon weight generation class
new polygon-to-polygon weight generation class wrapped around the versions CalcWeightEngine derived classes
Fixed bug that resulted in the output files from AggGen didn't write the feature_ids following parallel or dask calculations.
Fixed bug in xarray dataset return from AggGen didn't write feature_ids.
Add checks on AggGen file output to make sure feature_ids are being written for all data writers.