Added quantity to licences

Main changes:
- added quantity to licence model
- created new widget based on formset (see screenshot)
- moved licence module to new app structure
- cleaned up urls.py
![image](https://cloud.githubusercontent.com/assets/351535/4541917/12554888-4e1b-11e4-8d00-22475693f160.png)

@quamilek @xliiv please review.