1.  Add tests to ensure that non-zero length symlinks get dealt with properly
    both for parsing and for writing back out (don't write them out, they have
    bogus data).
2.  Add tests to ensure that Rock Ridge CE records are the very last record in
    the Rock Ridge extensions (some OSs, like FreeBSD, doesn't like them if
    they aren't the last one).
3.  Add a test for Rockridge RR entries in 1.12 version ISOs.  This isn't
    technically allowed by the standard, but we have seen it in the wild, so
    we should have a test to make sure we don't break it.
4.  Add a test for "bare" El Torito section entries.  The El Torito standard
    requires that section entries beyond the initial entry all start with a
    section header, but we've seen ISOs in the wild where this isn't the case.
    Add a test to ensure that these entries still work.
5.  Add a test for when the El Torito boot catalog record is in a Rock Ridge
    Continuation Entry.
6.  Add a test for when the El Torito boot catalog record is in a Rock Ridge
    relocated directory record.
7.  Break the API for progress_cb(), by making sure the user always has to
    have a function with a 3rd opaque argument.
8.  Allow removal of El Torito entries without removing El Torito altogether.
    To do this, we'll need to look up the bootfile when removing and only
    remove the entry that corresponds to it, or the whole thing if it is
    the initial entry.
9.  Show the "logical" Rock Ridge tree in pycdlib-explorer when the user
    requests the "rr" print mode.  This essentially means relocating Rock Ridge
    deep directory trees as appropriate.
10. Support the genisoimage options to allow relaxed ISO9660 filenames.
11. Add parsing tests against xorriso.
12. Remove the deprecated methods get_and_write(), get_and_write_fp(),
    add_joliet_directory(), rm_joliet_directory(), list_dir(), and get_entry().
13. Add the ability to hard-link from El Torito Initial and Section entries to
    ISO9660, Joliet, and UDF.
14. It should be possible to implement add_hard_link_in_place() and
    rm_hard_link_in_place(), provided that the addition/removal doesn't affect
    the number of extents for the parent DirectoryRecord/UDF File Entry.
15. Add support for the rest of the "walk" API to make it more compatible with
    os.walk().  In particular, support the topdown, onerror, and followlinks
    flags.
16. It is apparently possible to make an ISO that has *only* El Torito floppy
    booting on it (with no PVD and hence no filesystem; see
    http://www.menuetos.net/cdboot.htm for an example).  This is pretty
    esoteric, but might be interesting to support creating/parsing.
17. According to this post: http://reboot.pro/topic/21664-makeiso/?p=205285, the
    sizes specified for El Torito floppy disk sizes aren't actual sizes, but
    are instead specified as T/H/S, where H and S are fixed and column
    corresponds to 'size'.  Thus, it should be possible to support booting from
    so-called 'super-floppies'.  This doesn't entirely jive with the El Torito
    specification, but apparently most modern BIOSs support this.  We should
    fix PyCdlib for this.