Tweet Charts added for better tweet streak view

Today I added tweet charts, similar to GitHub's contribution charts. The existing implementation was making the list view too cluttered. Since users tweet almost everyday, the blog and newsletter posts was getting lost deep down the list.

With this new view, all the tweets are shown in the graph chart like above. In the list view posts section, tweet counts are only shown if there is at least a post or a metric record.

In addition to this, I also added last activity date on home page to easily track when a space had an update.