ENH : two enhancements
ENH : two enhancements

Provide more exposed details about the fill rules and the
dimensionality of the data in each column.

Improved validation of the column specs

ericdill/datamuxer,tacaswell/dataportal,NSLS-II/datamuxer,danielballan/datamuxer,ericdill/replay,NSLS-II/replay,NSLS-II/replay,NSLS-II/dataportal,ericdill/databroker,tacaswell/dataportal,NSLS-II/dataportal,ericdill/databroker,danielballan/dataportal,danielballan/datamuxer,danielballan/dataportal,ericdill/replay,ericdill/datamuxer