TODO list:

Library (and utility):
- Add support for CRC checking mp3wrap files.
- Add support for uncompressed .zip.mp3 files.
- Add support for uncompressed .rar.mp3 files.
- Add support for ordinary, unrwapped mp3s. (??)
- Make it a shared (dynamic) library too. (Not hard, just lazy. :) )
  Also not really something to push for. The lib is small and in flux. A new
  version will most probably be binary incompatible with earlier versions.
- Add support for chaining and unchaining Ogg files and optionally adding
  a filename tag to each chain.
- Fix .h generation somehow. Having two separate headers like this is ugly.
- Make wrapped files filenames UTF8. (??)
- Allow storing of relative paths.
- Add support for more ID3v2 tags, like embedding data. (??)
- Make checksumming code checksum both the area specified by the normal tag and
  the area specified by the redundancy tag as well as combinations of them -
  real offset and redundant size and vice versa. Doing that, less alternative
  stream checks should probably be done, to minimize false matches.
- Calculate and check against nometa checksums ONLY when regular MD5 doesn't
  match. Now it is always calculated and so checksumming takes double CPU time
  it needs to on a healthy file. A small test has shown that the checksumming
  is, for me at least, I/O bound and not CPU bound. The current solution is
  suboptimal, but works well.
- Add support for and test on more platforms.
- Make sure ID3 frame headers are generated correctly. The size of generated
  frames may become an issue if size > 127, depending on version (2.3 or 2.4).

Utility only:
- Most code in do_list exists in do_unwrap. Combine them?