eiExpand - Utilities for Expanding Functionality of 'eiCompare'

Augments the 'eiCompare' package's Racially Polarized Voting (RPV) functionality to streamline analyses and visualizations used to support voting rights and redistricting litigation. The package implements methods described in Barreto, M., Collingwood, L., Garcia-Rios, S., & Oskooii, K. A. (2022). "Estimating Candidate Support in Voting Rights Act Cases: Comparing Iterative EI and EI-R×C Methods" <doi:10.1177/0049124119852394>.