sl_options.txt

No argument formats:
    --foo  must be argument all by itself
    -f     can have other single character options after the first one

Required argument formats:
    --foo <arg>  option argument is in following command line argument
    --foo=<arg>  option argument is in the SAME command line argument
    -f <arg>     option argument is in following command line argument
    -f<arg>      option argument is in the SAME command line argument
    -f=<arg>     option argument is in the SAME command line argument

Optional argument formats:
    --foo=<arg>  option argument is in the SAME command line argument
    -f<arg>      option argument is in the SAME command line argument
    -f=<arg>     option argument is in the SAME command line argument
    --foo <arg>  NOT ALLOWED: see note below
    -f <arg>     NOT ALLOWED: see note below

    Note on optional arguments.  These are confusing, as the "natural" way for many would be to make the option argument
    be a separate command line argument.  This won't work for optional arguments, however, because there's no way for
    slOptions to distinguish between the optional argument and some unrelated option.  For example, consider the following
    command line, where -foo is an option with an optional argument:

        command -foo /dev /home

    Is the argument "/dev" the optional argument for -foo, or is it a separate argument for command?  There's no way
    for slOptions to determine that, so the only safe behavior is the one described above, wherein optional arguments
    MUST be part of the same command line argument.  So in this case, slOptions would process -foo without the optional
    argument, and would pass "/dev" as an argument to command.

Special options (all in a single command line argument):
    -       stop all option processing at this point; rest of options handled outside slOptions
    --      stop all option processing at this point; rest of options handled outside slOptions
    --?     turn on slOption's debug tracing (must be the first option argument)

Program configuration:
-- a short option name of ' ' is a special case to handle the standalone '-' option