Increase nodification panel width

Per #269 this should make the notifications feel less cramped. Here we
increase the width from 15em to 17.5em and use the entire window height.

Before: 
![screen shot 2013-08-01 at 12 34 54 pm](https://f.cloud.github.com/assets/1697198/895273/0d51fdbe-fac9-11e2-8982-ed158dc37bf2.png)

After:
![screen shot 2013-08-01 at 12 34 24 pm](https://f.cloud.github.com/assets/1697198/895277/1399ea42-fac9-11e2-9641-d5557bafc414.png)