add breadcrumb like context to favorites

Adding a little more info to data returned for the post summary, and using it for context on the favorites page.


Not a UI/UX guy, so feel free to ditch/tweak the favourites.tpl change.

Also thoughts on either Validating/sanitizing all data on the way in before storing, or moving sanitization more centrally like the get*Fields calls to avoid sanitization code everywhere (or worse forgotten)?