Added display method to ViewTree to customize display policy
Added display method to ViewTree to customize display policy

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