TODO for the nearest future:
- Add proper debugging facilities.
- Create a more generic way of mapping a pathname to a file. There are some path
  lookups we'd like to be able to run more than once.
- When calling open, buffer the file descriptors, so we don't open them each
  time, and just read from the filedescriptor.
- Make some way for the lookup functions to see more than just one
  field from the SQL row (eg. we need to create paths like "artist - song")
- Escaping string: when querying sqlite, replace ' with '' in ingoing
  strings. (why isn't this done in the API?)