Added optional elapsed_time functionality to ProgressBar
Added optional elapsed_time functionality to ProgressBar

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