Use different notification icons for different features

![device-2016-12-13-151008](/uploads/2c9aa33c230738b5ea20a76ac5e3b214/device-2016-12-13-151008.png)
![device-2016-12-13-150954](/uploads/85acd46fc6afd3aebcc1fcd015b041d7/device-2016-12-13-150954.png)

Closes #795

See merge request !460