Unread entries badges display "999+" if there are more than 999 unread entries.

This is achieved with a new angularjs filter.

This is desirable to keep badges from getting arbitrarily wide. If badges get too wide, at a certain poing they "jump" to a second row in the sidebar, making it look ugly. By limiting their width it can be ensured that the sidebar is properly displayed in all cases.
Unread entries in folders are calculated based on unread entries in feeds.

This means that the unread_entries value for folders is no longer used by the view, and it can be removed along with all code related to it.
Removed the "unread_entries" column from the Folders table. Also removed all code related with that field.

It's no longer necessary to keep an up-to-date count of all unread entries in a folder. Since adopting angularjs, the view can infer that number from the unread entries counts of each feed in the folder.

This should also speed up subscribing, unsubscribing and refreshing feeds.