* add expansion of default values in help text: the string
    "%default" in an option's help string is expanded to str() of
    that option's default value, or "none" if no default value.
  * bug #955889: option default values that happen to be strings are
    now processed in the same way as values from the command line; this
    allows generation of nicer help when using custom types.  Can
    be disabled with parser.set_process_default_values(False).
  * bug #960515: don't crash when generating help for callback
    options that specify 'type', but not 'dest' or 'metavar'.
  * feature #815264: change the default help format for short options
    that take an argument from e.g. "-oARG" to "-o ARG"; add
    set_short_opt_delimiter() and set_long_opt_delimiter() methods to
    HelpFormatter to allow (slight) customization of the formatting.
  * patch #736940: internationalize Optik: all built-in user-
    targeted literal strings are passed through gettext.gettext().  (If
    you want translations (.po files), they're not included with Python
    -- you'll find them in the Optik source distribution from
    http://optik.sourceforge.net/ .)
  * bug #878453: respect $COLUMNS environment variable for
    wrapping help output.
  * feature #988122: expand "%prog" in the 'description' passed
    to OptionParser, just like in the 'usage' and 'version' strings.
    (This is *not* done in the 'description' passed to OptionGroup.)