Added caching feature.
App will now use local storage (totalStorage.js) to cache blog posts.

When the app starts, all posts in the cache are rendered immediately to
the DOM. While rendering, the app will also try to retrieve the RSS feed
from www.felicious.com, and render only the new items.

Cached posts are rendered under the 'cached-items-node' div and new
items are rendered under the 'new-items-node' div. Check index.html

This feature makes the blog load almost instantly.
Look into adding a [+10]-like button if user is scrolling while update
finishes, so that the scrolling isn't messed up.