Updated timeline colors

From #22

Finished up the color scheme for the timeline. Did a little decomposition, but the API's still the same. I'm planning on cleaning up more once I get deeper into implementing to the prototype.

One kinda big change is that the actual timeline is split into two separate SVGs―one for the header and one for the actual timeline region. I think it'll make some of the click handling a little easier later on, but if you'd rather I push them together into one SVG, I'll do that.

A couple screenshots:

![screen shot 2014-10-17 at 11 27 24 am](https://cloud.githubusercontent.com/assets/6354033/4683926/77e212fe-562b-11e4-9d9a-be8cea6ace56.png)

![screen shot 2014-10-17 at 11 29 24 am](https://cloud.githubusercontent.com/assets/6354033/4683938/8de15ed4-562b-11e4-863f-28c2666f91c3.png)