Set default of depth=1 in HoloMap.relabel method
Set default of depth=1 in HoloMap.relabel method

This change is discussed in issue #117

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