Embedded icon assets to polymer css

Designed (along with Devon) and embedded icon assets to polymer css.

Here is an example of all three (hardcoded for display):

![image](https://f.cloud.github.com/assets/357955/1872630/92a1b226-78a9-11e3-86a9-7b061e73cdcb.png)

review @devoncarew @dinhviethoa