Feature/playlists

this adds the playlists to our app. some screenshots:
![playlist1](https://cloud.githubusercontent.com/assets/275897/5555072/a1c31c16-8c91-11e4-8281-7547e1354921.PNG)
![playlist2](https://cloud.githubusercontent.com/assets/275897/5555073/a316565a-8c91-11e4-93e4-045617a88077.PNG)
![playlist3](https://cloud.githubusercontent.com/assets/275897/5555074/a447fcea-8c91-11e4-85a5-ae29653a9d21.PNG)
![playlist4](https://cloud.githubusercontent.com/assets/275897/5555075/a4c2a9fe-8c91-11e4-97be-134091f2ce47.PNG)