Need a repeatable file property
We have a customer who needs a pqPropertyWidget that displays a list-view whose rows are file-property widgets (i.e., an editable path with a "..." button for browsing the filesystem). The server-side StringVectorProperty will be extensible, so the property-widget should have the typical "+/-/x" buttons to the right of the list view. The StringVectorProperty will have a FileListDomain.