Calculate Enrichment from Virtual Screening

The `analysis.enrichment`_ helps to calculate enrichments based on known actives and the number of decoys in screen.

from schrodinger.analysis.enrichment import calculator
efcalc = calculator.Calculator(
    actives = "my_actives.txt",            # Active titles, one per line.
    results = "screen_results.mae",        # Glide pv file.
    total_decoys = 1000
efcalc.report()                    # Print default report to standard out.
efcalc.savePlot()                  # Create default graph png.
print(efcalc.calcBEDROC(alpha=20)) # Print the BEDROC metric value