refactor the summary stat procedure into a separate method
refactor the summary stat procedure into a separate method

piotr-gawron/pileup.js,snaheth/pileup.js,snaheth/pileup.js,hammerlab/pileup.js,hammerlab/pileup.js,piotr-gawron/pileup.js,snaheth/pileup.js,hammerlab/pileup.js,hammerlab/pileup.js,snaheth/pileup.js,piotr-gawron/pileup.js,piotr-gawron/pileup.js