Fix last tweet scraping

Funny thing is, those jQuery selectors work fine in DevTools. So, twitter must be serving a different page to `request`.

Anyway, this gets it working again.

![last](https://cloud.githubusercontent.com/assets/357481/3006847/98224458-de53-11e3-931f-16d24f641bb1.png)

![last-djm](https://cloud.githubusercontent.com/assets/357481/3006848/9ce6097a-de53-11e3-8b08-ddeb1fc172fa.png)