removed TODOs as we keep track of everything as issues now.

TODO.md

-- [*] list notes of predecessor, if available, on show detail page
-- [ ] list notes of successor, if available, on show detail page
-- [*] optimize the export for the day schedule
-- [ ] handle exceptions better
-- [ ] optimize the selection of a predecessor for a show
-- [ ] optimize the selection of a timeslot for a note
-- [ ] add management command to automatically renew program slots
-- [ ] add jingle field (File) to Show model
-- [ ] customize the admin interface for program slot