updates pearson and r_squared to consider epsilon#562

samland1116 merged 5 commits intomainRTIInternational/teehr:mainfrom

556-divide-by-zero-still-occurs-with-add_espilson-true-for-pearsoncorrelation-and-rsquaredRTIInternational/teehr:556-divide-by-zero-still-occurs-with-add_espilson-true-for-pearsoncorrelation-and-rsquaredCopy head branch name to clipboard