Package category

[ldecicco-USGS]

We're trying to categorize all the USGS-R packages, as described here:
https://owi.usgs.gov/R/packages.html

I'd recommend this package as "Research". When you decide what you think this package should be, add a badge to your readme:

If you wanted to include a link or note in your package startup message, we added that to some packages too. For example:

https://github.com/USGS-R/smwrQW/blob/master/R/smwrQW-package.R#L29