plot_radar: Create radar (spider) charts from a data frame

Description

This function creates a radar chart. Original Code: http://statisticstoproveanything.blogspot.co.uk/2013/11/spider-web-plots-in-r.html

plot_radar(data, data.row = NULL, y.cols = NULL, main = NULL, add = F, col = "red", lty = 1, scale = T)