--- MAIN FUNCTIONS ---
pga                     main variable selection routine
get.topfew              what are the top-ranked variables?
get.pga.ans             which variables received significantly more votes than others?
view.bubble             creates a bubble plot of the result
view.order              creates an order plot of the result
view.movie              creates a dynamic bubble plot of the result
sga                     run a single-path genetic algorithm; called by pga

--- OTHER FUNCTIONS ---
summarize.PGAsim        used to summarize repeated simulation results
