[notification] Color for Notification

- Add configurable Color for notifications.
- Update translations.
- PEP8 / Lint compliant.

![temp](https://f.cloud.github.com/assets/1189414/2443149/37a983d8-ae2f-11e3-9890-0bc1f7517b2d.jpg)

Brancho: feature/notification2 :palm_tree: