electsys21 - Voting Methods for Ranked, Rated and Approval Ballots

Implements a range of voting methods and electoral systems for determining election winners, including the D21 method with and without minus votes (Janecek, <https://www.ih21.org/en/d21-janecek-method>), first-past-the-post, two-round runoff, instant runoff, the Borda count, approval voting, majority judgement and the Condorcet method. The functions accept several ballot formats - ranking, cardinal utilities, approvals and scores - with automatic detection of the input type, configurable tie-breaking and tidy summaries of the results.