API and JS changes:
1. Return number of unread posts when doing a GET on /feeds/.
2. Set up initial logic to only download unread posts when asked by user.
Update post counts for All entry.
clear posts when choosing a different entry and set CSS style for selected entry appropriately
dynamically adjust menu options based on selected feed
update feed unread counts from server every five minutes.
temporarily disable mark as read due to jquery issues. mark as read when article title is clicked upon.