news feed: remove grouped/ungrouped; help is tooltip; new tabs
refactoring: split feeds logic into db->feeds module
/api/feed supports "tab" option; also, document it in API.md
tabs in news feed are working
new pills style
upgrade bootstrap - no more .nav-*
attach tooltip directly to tab name in news feed
Merge branch 'feed-tabs'

http://questhub.io/realm/meta/quest/52385e7f1e17e13965000043
update "not following any" alert in news feed
rebuild static