Added range implementations to Columns interface
Added range implementations to Columns interface

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