Problem to solve: there's a mix between API usecases for Playlist-UI and Website.

See #22

Shall we still put this in a sub app?
Would still need to figure out how to hook from the sub app into the serializer viewsets (and not vice versa) in order the custom fields get saved.

See #21

Only Admins (if is_staff is True) may access these Models for reading/writing.

Linking notes to timeslots also uses the REST API now.

Adding/Updating/Deleting schedules including collision detection is still a to-do.

See #22

Updating is constrained to defined fields.
See #22

Implemented django-oauth-toolkit for authentication.

Working on prototype for playout API (momentarily still called week_schedule())

Added permission restrictions for common users in APIs
See #23

Added playlist_id to TimeSlot datamodel
See #21

Made some minor changes in calendar.