Integrate with ArcHydro

[Castronova]

Marouane Temimi at Stevens Institute of Tech suggested that we look into adding a NWM Subsetting package to the ArcHydro toolbox. This would compliment other related tools such as HAND processing. It's unclear whether this is a good fit for a GIS toolbox. Perhaps it would align better if our API accepts Shapefiles or GeoJSON as input to define the subsetting area.