added test for dataset.filtercolumns
added test for dataset.filtercolumns

devinit/datawrapper,motherjones/datawrapper,ThuyNTran/datawrapper,elaOnMars/datawrapper,qqming113/datawrapper,grepman/datawrapper,ThuyNTran/datawrapper,rubensfernando/datawrapper,grepman/datawrapper,robmcloughlin/Insights,robmcloughlin/Insights,qqming113/datawrapper,elaOnMars/datawrapper,grepman/datawrapper,washingtonpost/datawrapper,rubensfernando/datawrapper,plusgut/datawrapper,devinit/datawrapper,washingtonpost/datawrapper,grepman/datawrapper,plusgut/datawrapper,elaOnMars/datawrapper,washingtonpost/datawrapper,rubensfernando/datawrapper,qqming113/datawrapper,elaOnMars/datawrapper,kendrick-k/datawrapper,grepman/datawrapper,grepman/datawrapper,datafunk/datawrapper,washingtonpost/datawrapper,robmcloughlin/Insights,ThuyNTran/datawrapper,qqming113/datawrapper,devinit/datawrapper,datafunk/datawrapper,datafunk/datawrapper,datafunk/datawrapper,elaOnMars/datawrapper,plusgut/datawrapper,kendrick-k/datawrapper,robmcloughlin/Insights,kendrick-k/datawrapper,devinit/datawrapper,qqming113/datawrapper,plusgut/datawrapper,kendrick-k/datawrapper,qqming113/datawrapper,datafunk/datawrapper,washingtonpost/datawrapper,datafunk/datawrapper,devinit/datawrapper,ThuyNTran/datawrapper,devinit/datawrapper,ThuyNTran/datawrapper,kendrick-k/datawrapper,motherjones/datawrapper,motherjones/datawrapper,elaOnMars/datawrapper,rubensfernando/datawrapper,ThuyNTran/datawrapper,rubensfernando/datawrapper,robmcloughlin/Insights,washingtonpost/datawrapper,motherjones/datawrapper,kendrick-k/datawrapper,motherjones/datawrapper,motherjones/datawrapper