Merge branch '327-empty-state-design' into 'master'

Simple Empty State Messages

This MR implements very basic and simple empty state messages for the
current features.

This is how it looks (note that the contact add FAB will be removed soon):

![Screenshot_20160629-125146](/uploads/4c6a8be041cc48b0aba165dd507453d5/Screenshot_20160629-125146.png)
![device-2016-06-29-130834](/uploads/821677074d7d3e6435574a0711f3a0a7/device-2016-06-29-130834.png)
![Screenshot_20160629-125138](/uploads/a39a465db51f8e009ab0b6ee34d4a7e7/Screenshot_20160629-125138.png)
![Screenshot_20160629-125853](/uploads/1dab114bbe7ba379b20a5d298c8fa25c/Screenshot_20160629-125853.png)

Closes #327

See merge request !236