Jango service integration

First functional version of Jango service integration for Nuvola Player 3

Features of previous integration for Nuvola 2 are working: play / pause / thumb up / thumb down / song info and art.
The thumbs up/down actions don't seem to be toggle actions. When I click thumbs up, the track is added to favorites. However, when I click the button again, the track is not removed from favorites as it should be in toggle actions. Same for thumbs down action. They should be simple actions.