Fix to CompositePlot.get_frame method
Fix to CompositePlot.get_frame method

Fixes per frame normalization across a Layout

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