Allow a mechanism to go from a composite dataset of polydata to a single polydata
When outputting certain files (e.g. .ply files) we need to have polydata so it would be good to have a mechanism to go from a composite dataset of polydata directly to a single polydata. As far as I can tell, currently the best mechanism in PV is to go use the Merge Blocks filter and then the Extract Surface filter but it would be nice to be able to reduce the workflow down to a single filter to do the operation.