added under/over sampling, feature scaling, and impact coding
added under/over sampling, feature scaling, and impact coding

HealthCatalystSLC/healthcareai-py,HealthCatalyst/healthcareai-py,jpo/healthcareai-py,mxlei01/healthcareai-py,mxlei01/healthcareai-py,jpo/healthcareai-py,HealthCatalystSLC/healthcareai-py,HealthCatalyst/healthcareai-py