Improved validation error message for options supplied in __call__
Improved validation error message for options supplied in __call__

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