TODO for the nearest future:
- Add proper debugging facilities.
- Add some generic way of logging, possibly using any fuse API available to do
  this.
- 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. We could behave more fs-like by
  having lists of active nodes as an analogue to inodes in a typical filesystem.