Fix for bug: error if there were one or more data columns with 0 non-missing data points. Fixed by removing columns with only missing data points before testing the class of the columns.
Fix for bug: error if there were one or more data columns with 0 non-missing data points. Fixed by removing columns with only missing data points before testing the class of the columns.

thehyve/heim-SmartR,thehyve/heim-SmartR,thehyve/naa-SmartR,agapow/smartr,thehyve/naa-SmartR,thehyve/naa-SmartR,agapow/smartr,thehyve/heim-SmartR,thehyve/heim-SmartR,agapow/smartr,agapow/smartr