multiple url polling code, refactore posts list and home page UI
hooked up UI to support multiple context subscription
polling multiple urls working, comments added
tidy up feed.js
Merge pull request #23 from mozboz/twofeeds

Now supports multiple feeds: personal feed + multiple added contexts
Merge branch 'master' into flexbox

Conflicts:
	client/layout/header.html
	client/views/posts/post_item.html
	client/views/posts/posts_list.html
fixed broken parts of merge