faceting.Term object
facet term page w description, parent, children, search results
faceting.Facet object
term ancestors
experimental tree function for facet pages

It uses autovivification! On the other hand it's unsorted.
Merge branch 'branding1' of https://github.com/densho/ddr-public into branding1

Conflicts:
	ddrpublic/ui/faceting.py
	ddrpublic/ui/templates/ui/browse/facet.html
	ddrpublic/ui/templates/ui/browse/term.html