Support highlighted state for inactive parents of active child items

With the facetapi feature request: #1325456: Add a third facet item state for expanded hierarchical facets.
Widgets will be able to see hierarchical information about their items. Collapsible Facets should be aware of this and theme items accordingly.
Attached is an example patch based on the proposal patch in #1325456: Add a third facet item state for expanded hierarchical facets.