Angularjs code retrieves entries for feeds/folders from the nested routes created in c1d275229e632084ac0fc5b6eb85f2bba977407a
The FeedsController#show action now returns a JSON document describing the feed, instead of an array of entries in the feed.
The FoldersController#show action now returns a JSON document describing the folder, instead of an array of entries in the folder.
WIP: after clicking on a feed in the sidebar, retrieve that single feed via AJAX to update it.

Normally the only value that can actually be updated is the unread entries count.