Added optional group parameter to Settings and support in SettingsTree
Added optional group parameter to Settings and support in SettingsTree

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