golosovRST - Golosov Relative Size Triangle Classification and Plotting

Computes coordinates for the Golosov Relative Size Triangle (RST), classifies party-system observations into Golosov subtypes using polygon mapping and produces publication-ready Relative Size Triangle plots. Method reference: Golosov, G. V. (2011) "Party system classification: A methodological inquiry" <doi:10.1177/1354068810377189>.