Added iTerm2 dark theme

Here are some pictures:
![screen shot 2013-11-16 at 7 35 40 pm](https://f.cloud.github.com/assets/2314074/1557614/a9bc383c-4f28-11e3-8d61-a28c6de96e99.png)
![screen shot 2013-11-16 at 7 36 07 pm](https://f.cloud.github.com/assets/2314074/1557615/ac8b5a52-4f28-11e3-8d23-aa547c0f86de.png)

I am using the fish shell, so don't take the name of the command as part of the theme (notice how `ls` is blue).