Add simple test for ColumnTypes
Add simple test for ColumnTypes

tpetricek/Deedle,Dependencies/Deedle,jeyoor/Deedle,BlueMountainCapital/Deedle,buybackoff/Deedle,AtwooTM/Deedle,Dependencies/Deedle,AtwooTM/Deedle,tpetricek/Deedle,caioproiete/Deedle,BlueMountainCapital/Deedle,filmor/Deedle,caioproiete/Deedle,filmor/Deedle,jeyoor/Deedle,jeyoor/Deedle,Dependencies/Deedle,buybackoff/Deedle,caioproiete/Deedle,buybackoff/Deedle,BlueMountainCapital/Deedle,AtwooTM/Deedle,filmor/Deedle,tpetricek/Deedle