clean up buttons in footer of Account Settings page

# mobile width
![settings-mobile](https://cloud.githubusercontent.com/assets/203725/5040402/0baa8074-6b63-11e4-8189-89d1eb00b8e5.png)

# desktop width
![settings-desktop](https://cloud.githubusercontent.com/assets/203725/5040403/0baa8952-6b63-11e4-9de1-f6729a3e3bc9.png)

not necessary, but it helps differentiate the "Save Changes" style from the other buttons' styles. I'm not attached to this change.