* add subspaces to be listed with edit_hash/spaceAuth authorization
* remove dead code from api_helpers.js
* add edit_hash authorization for requested space thumbnails
* handle /s/:hash links in frontend router
* set space_auth via a function, allow passing it to load_space
* rename variable in /s/:hash router in backend
* hide search, profile, breadcrumb in folders if not logged in, construct links to subspaces differently for anonymous editors