Add favicon

Appears to be working in dev, I put this in the static folder rather than media, following the ka-lite repo example -- @jamalex lmk if that's not kosher. Otherwise this should be good to go:

![image](https://f.cloud.github.com/assets/1319950/2287812/bab08d72-9ff1-11e3-9d1a-c2f25be2b3fa.png)