Added initial version of Columnar_Data Tutorial
Added initial version of Columnar_Data Tutorial

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