Add inbox/archive section

Here's what it looks like:
![ios simulator screen shot 04 apr 2014 22 25 53](https://cloud.githubusercontent.com/assets/124243/2619989/7012d812-bc37-11e3-872d-78312f189fd1.png)
![ios simulator screen shot 04 apr 2014 22 25 55](https://cloud.githubusercontent.com/assets/124243/2619990/725bae1e-bc37-11e3-97f8-836aa3a6d39a.png)