Add tagline and faq link to homepage.

@spladug

Adds a descriptive tagline to the live homepage and a link to the faq (which is more straightforwardly explanatory than /r/live).

![screenshot 2014-09-03 10 31 10](https://cloud.githubusercontent.com/assets/1231913/4138438/fb7fd910-3390-11e4-8f06-3978184c6b6a.png)