Fix youtube in modal

- Fixed youtube in modal. It now fluid and added a button for full
screen

Fixes https://github.com/styxit/HTPC-Manager/issues/202

![image](https://cloud.githubusercontent.com/assets/1214134/2794766/e87cb822-cbf0-11e3-8634-a351e823734e.png)

![image](https://cloud.githubusercontent.com/assets/1214134/2794774/073224be-cbf1-11e3-817b-a9448ddf6a2c.png)