MUMUP-998 & MUMUP-986: Implement notification icon styles

Implementing styles for the notification icon in the menu bar on the upper left. After playing with different styles and forms, came up with a rounded square/rectangle with white/cream background-color. When user has zero notifications, background-color changes to red to match the menu bar (gives the impression of being empty). 

I added some javascript to change the class to give it these styles when feed.length=0, but not sure how to test that it's working. We will probably want to do this before merging it in.

Before:
![image](https://cloud.githubusercontent.com/assets/1919535/3922561/9b7b6c2a-23cb-11e4-8a8d-30855c97d10f.png)

After:
![image](https://cloud.githubusercontent.com/assets/1919535/3922639/5eec6934-23cc-11e4-91ce-969f0e47cad0.png)


First pull request yea!