adds file type icon support based off of mime type of a file

Closes #51 

Adds the most common file type translations to font awesome file icons.

![screen shot 2014-10-14 at 11 31 07 am](https://cloud.githubusercontent.com/assets/1656824/4634439/4c0165a2-53d0-11e4-97d9-11f1fff75932.png)