New look for "notes" in SettingsUI

- use `<em>` to reduce a little bit the font and darken the strings
- `<aside>` now only works as a regular 'aside' instead of making the text
  italic
- color used (just a darker text-color) #838587

![capture](https://cloud.githubusercontent.com/assets/6444179/3497614/4fa49d68-05ed-11e4-84ec-77221e7c9e22.PNG)