Updated Structure class to use existing permalinks, rather than creating them.
Also moved any other url-generation code to the view, and out of the class.
Affects #302 #102
Updating API to not use page-head, map to new routing system. Affects #302 #102, Resolves #373
Fixing up structure page to use fixed API calls, and copy how we get structures in the API for consistency.  Affects #302 #102 #285