Made Columns dataframe version compatible with older pandas
Made Columns dataframe version compatible with older pandas

ioam/holoviews,vascotenner/holoviews,ioam/holoviews,ioam/holoviews,vascotenner/holoviews,basnijholt/holoviews,mjabri/holoviews,mjabri/holoviews,vascotenner/holoviews,basnijholt/holoviews,mjabri/holoviews,basnijholt/holoviews