Changes between btype 0.3.1 and 0.4.0:
* GUI improvements here and there.
* Some code cleanups, including the addition of license headers and vim
  modelines where missing.
* Start with a new document on startup.
* You can now change values of Strings and Ints, and change the names of
  Dict keys using the inline list view renamer.
* Better handling of binary data.
* You can now add to empty files.  Not sure why you'd want to, but it wasn't
  hard to implement.
* btype nows asks if you want to save changes when you're about to lose your
  data.
* btype will display the SHA1 hash of the selected item in the status bar.  No
  special reason other than as a quick way to check the SHA1 value of the info
  hash for debugging.
