Added favicon

This adds a favicon from issue https://github.com/balanced/balanced-dashboard/issues/241.

Here is a screenshot of the favicon in action:

![image](https://f.cloud.github.com/assets/105835/657777/316b372e-d585-11e2-8fd9-bc4b1f39bf62.png)

Since local URIs can't be displayed in Chrome (/sadface https://code.google.com/p/chromium/issues/detail?id=51270), I uploaded it here for local verification for the person to review this. It is available [here](http://f.cl.ly/items/3E0x2H2J302X2I3D190C/favicon.ico).