Removed incorrect use of _abstract = True in Overlay
Removed incorrect use of _abstract = True in Overlay

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