Dashboard content

:construction_worker: 

Display a user's cookbooks and collaborated cookbooks on the Dashboard sidebar
in addition to useful community links. This also adds a placeholder for the
Activity Feed section of the Dashboard.

Note: there are no styles for this content.

Here is what this awfulness looks like:

![screenshot from 2014-04-29 11 52 34](https://cloud.githubusercontent.com/assets/928367/2831175/51b5b712-cfb6-11e3-94ef-927062c53308.png)