TODO

o Fix the display code for channels. In Germany it is only the name,
  for other countries it is a bad mix between names and access ids. It
  should be a simple list of display names, all in the db. Let the
  user (or freevo tvserver) face the naming / access problem.

o Remove the automatic stop detection. It won't work with not sorted
  files. And if you sort the file using tv_sort, you will also get
  correct stop times. So no need for that extra code.

o It could be possible to have blanks in the guide. E.g. the German
  children channel stops at 9pm and starts again in the next
  morning at 6am. So when I request the program for 10pm, maybe
  return a dummy program with start=9pm and stop=6am and valid=False
  or something like that. Similar to this, what happens if you have
  an older guide without current data. Maybe also a dummy program
  with start=last_stop and stop=very_big_number.

o Make updates possible. If I already have a valid db and add a new
  program, check

   a. if something is overlapping there because of schedule
      changes. If you search for start in range(start, stop) and 
      stop >= start, you should get one result max. If you get more,
      delete them from the db. And if you have one, start and stop
      should match exactly, if not, delete it.

   b. now if you have one overlap and start and stop are the same,
      check the attributes. If everything is the same, no need to
      change the db, just quit. If something is different, change the
      object, not add a new one.

   c. if no overlapps, add new program like you do it now.

o Clean up db. It would be nice to have some sort of history. But on
  update, delete every program older than lets say 7 days.

o Import more data from sources (like ratings, advisories, actor names, etc.)

o Assign ids to unique programs regardless of air times (this is already
  given by zap2it, but not sure about other listing providers -- may need to
  code custom heuristics).