Timeline status view

Part of #93.

![download](https://cloud.githubusercontent.com/assets/246103/5562641/9f83a576-8e24-11e4-92ca-1266dde7d785.png)

Yet to be done:

- [ ] Show a "no incidents today" message for days where nothing was reported.
- [ ] Maybe increase the contrast of the `.date` class.
- [ ] Decrease the height of each message item as there is a lot of wasted space.

Thoughts and comments please.